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We bought and tested the 21 top-rated ultralight backpacks from Gossamer Gear, ULA, Hyperlite, Zpacks, Six Moons Designs, Durston, and more to find the best pack for your needs.
Some of the best Ultralight Backpacks in our stable!
Credit: Justin Simoni
By Justin Simoni ⋅ Review Editor ⋅ Updated July 11, 2025
The right ultralight backpack provides just enough capacity to stash all your basic backpacking essentials while taking a load off your back so you can hike light and fast.
Over the past decade, our thru-hiking experts have logged hundreds of trail miles, testing more than 50 of the best ultralight backpacks around. We slogged along the John Muir Trail, wandered the Colorado Trail and CDT, hiked around Southern France's Haute Alpes, and traversed miles of talus in Argentine Patagonia.
The Gossamer Gear Mariposa is the best pack in our lineup for its ability to manage both light and heavy loads comfortably. The abrasion-resistant material is also durable enough to handle some long miles on the trail.
To lighten the load on your wallet, we also love what the less expensive Gossamer Gorilla 50 has to offer. From day hikes to multi-day adventures, this pack provides comfortable straps and a great set of features at a reasonable weight for a more affordable price.
Check out our other reviews of ultralight gear for more ways to shave a few ounces (or pounds) from your pack.
Editor's Note: We updated our review of ultralight backpacks on July 11, 2025, to add new versions of many of our favorite packs from Gossamer Gear, Nashville Packs, and Durston, and to add a new pack from Pa'lante.
Main pack fabric less durable than more expensive materials
Against relentless competition from other brands, the Gossamer Gear Mariposa 60 once again leads the pack. This ultralight pack balances comfort with an unparalleled emphasis on lightweight design. Its feature set is thoughtful and useful, but not overkill. The Mariposa offers plenty of external carry options without feeling weighed down by superfluous bells and whistles. It has one of our favorite stretchy center mesh pockets, which proved large enough to store extra layers, snacks, and other items we wanted to access quickly. It fits a bear canister and can carry a heavy load comfortably, yet it can also compress to carry a smaller load comfortably. “Sight unseen, if someone asks me what ultralight pack to grab, I instinctively tell them to grab the Gossamer Gear Mariposa. It works perfectly for just about everyone,” our main tester beams.
SPECIFICATIONS
Weight per Liter (Full Pack)
0.57 oz/L
Measured Weight
34.3 oz
Advertised Volume
60 L
Measured Volume (Main Compartment)
54 L
Stripped Weight
18.0 oz
Marketed as a 60-liter pack, the Mariposa can carry up to approximately 64 liters, if you stuff it to the brim and utilize all of its external pockets. For some, this might feel like too much room for an ultralight pack, as the more room you have, the more likely you'll fill it with unnecessary gear. It's also not the lightest pack we tested, though its 34.3-ounce total weight and 0.57-ounce per liter weight-to-volume ratio are impressive. The tradeoff for a bit of extra weight is an unbeatable level of comfort. The pack's fabric isn't the most durable, and, comparatively, some newer packs are starting to look very attractive. If you're looking to shed some ounces for a much lighter pack, the Mountain Laurel Designs Exodus 55L is about half the weight and is made from the much more durable (and much more expensive!) Ecopak UltraWeave. While the Exodus 55L offers a better weight-to-volume ratio, if comfort is a deciding factor, stick with the Mariposa. “I found this is one of the rare options that's comfortable right out of the box,” remarks our lead tester.
Great spread of features without compromising on weight
Versatile for day hikes and multi-day trips
CONS
Not as waterproof as other packs
Pack fabrics not as durable as more modern options
Top flap may not be everyone's favorite
Once you get used to the supreme comfort of the Gossamer Gear Gorilla 50, it's hard to imagine living without it. This pack is stacked with features — it has great back padding, an internal aluminum frame, and an excellent hip belt. “I love the Gorilla's voluminous external pockets. They swallow up so much gear that I rarely needed to open the pack's main compartment until it was time to make camp,” our lead tester brags. Even more impressive is the modular design that allows you to customize the pack for the trip's itinerary by easily stripping components off so that you may not need to cut gear weight.
SPECIFICATIONS
Weight per Liter (Full Pack)
0.64 oz/L
Measured Weight
32 oz
Advertised Volume
50 L
Measured Volume (Main Compartment)
45 L
Stripped Weight
16.2 oz
There's little we don't love about the Gorilla, and it will be difficult for anyone to wrangle it out of our greedy thru-hiking hands. Still, the top flap design of Gossamer Gear is unusual in our ultralight category. “Many hikers I know prefer a rolltop design,” claims our tester. If you're especially rough on gear, the mesh on the side and center pockets and for holding the back padding in place may become victims of your heavy-handedness. In that case, the exceptionally durable Dyneema construction of the Hyperlite Mountain Gear Porter 55 is a better pick, but it's not exactly a budget-friendly purchase. But if you don't need the extra durability, the Gorilla is a great buy.
A multitude of useful exterior pockets to store close-at-hand gear
Dyneema Composite Fabric is extremely durable and water-resistant
Comfy and embedded foam padding, hip belts, and shaped vertical stay
CONS
Heavier than other packs of the same total volume
Lack of load lifters
Good friends, food, views, and gear are critical for peak enjoyment while spending weeks at a time hiking a long trail. We found the Hyperlite Mountain Gear Unbound 40 to be our best ally when looking for an almost perfect pack for the long haul. The extremely durable and water-resistant DCH pack material means you don't have to worry about acute gear malfunction leaving you stranded several states into your long trail. The embedded foam padding, internal shaped stay, and hip belt all work in consonance to support moving the weight of your loaded pack and distributing it off your tired shoulders. “This is one of the most comfortable packs to shoulder at the beginning of a long carry,” lauds our lead tester. The massive exterior center and side pockets allow you to carry much of the gear you'll use throughout the day outside the main pack compartment. A sneaky bottom-of-the-pack stash pocket gives you a few more liters of storage.
SPECIFICATIONS
Weight per Liter (Full Pack)
0.87 oz/L
Measured Weight
34.6 oz
Advertised Volume
49 L
Measured Volume (Main Compartment)
35 L
Stripped Weight
26.0 oz
Comfort, carrying-ability, and convenience come at a cost. For the Unbound 40, it's a few more ounces on the scale when compared to some of the other packs we'd consider when going off the map for a few weeks. The main culprit is the more durable 150-denier polymer face fabric that adds so much insurance against downpours and abrasive rocks. Another is just how many useful, voluminous pockets you'll find on the Unbound 40. If you don't need so much carry capacity, look for a more minimalist pack that utilizes lighter materials. But for us, these included features stopped us from having a frustration-fueled meltdown on the trail more than a few times and allowed us to persevere to our next resupply smiling. “For long-distance trips, the exceptional carrying capacity and the weight transfer to my hips make the Unbound 40 a winner,” confides our lead tester. Try out the Ultralight Adventure Equipment Ultra Circuit for another long-distance trail-worthy pack with great storage capacity, comfort, and durability.
We took advantage of the local spring runoff to do an impromptu field test of the Unbound 40's water resistance. After our misogi cleansing, we found the contents of the main compartment to be relatively dry, thanks to the waterproof DCF, taped seams, and our triple folding the roll top.
Requires additional liner for greater water resistance
Adjustment straps can get in the way
For trips that demand a pack with tons of room to store gear, the Six Moon Designs Swift V is the most natural choice. We measured the internal volume at an impressive 55 liters — more than some other packs' total carrying capacity inside and out! A deep, external center pocket, easily accessible side pockets, cavernous hip belt pockets, and a smattering of pockets on the running vest-style shoulder straps round out the extensive carrying capability of this phenomenal high-capacity pack. “I loved the feeling of the Swift V's wide straps hugging my back tightly while I traipsed around,” adds our lead tester.
SPECIFICATIONS
Weight per Liter (Full Pack)
0.76 0z/L
Measured Weight
38.0 oz
Advertised Volume
50 L
Measured Volume (Main Compartment)
55 L
Stripped Weight
27.8 oz
While you will surely shoulder a number of extra backpacking accouterments with the Swift V, there is still a limit on how much weight it can handle comfortably – we suggest keeping loads below 35 lbs. Speaking of weight, as far as ultralight packs go, one with this much main compartment volume isn't ever going to be as light as smaller, more nimble packs. “Some of the features at that make the Swift V so comfortable are also what make it just a little heavier than other packs,” notes our tester. If you're concerned about minimizing pack weight while maximizing carrying capacity, check out the REI Co-op Flash Air 50. But in our opinion, the Swift V is the perfect pack when you're the one “lucky” enough to haul you and your partner's favorite two-person tent, or you need to bring along a bulkier, 0-degree sleeping bag for a chilly night in the alpine. It is an amazingly comfortable, do-it-all pack for long carries.
We must come clean and admit we're still blown away at the amount of engineering put into the exceptional Osprey Exos Pro 55 to take a more conventional backpack design and make it truly ultralight. Weight may be gone, but all the creature comforts that one expects from a backpack are not left on the cutting room floor. “I especially loved the back suspension system on this pack. It provided comfort from my pack's load and gave a ton of air circulation that my sweaty back desperately craves,” says our head tester.
SPECIFICATIONS
Weight per Liter (Full Pack)
0.60 oz/L
Measured Weight
33.2 oz
Advertised Volume
55 L
Measured Volume (Main Compartment)
46 L
Stripped Weight
30.4 oz
If you want to shave off as much weight as possible from your kit, the Exos Pro 55 won't be attractive to you since the frame, padding, and hip belts aren't removable, even if the top lid is. “Save this pack for your long hauls and use a more nimble pack for day trips,” admits our lead tester. That said, one can certainly make a proper sub-ten-pound base weight kit when using the Exos Pro, and for that, we applaud Osprey's effort. The main nylon fabric is built to last for years, but you should know that the back mesh on the suspension system might need to be babied a little more. Another worthy alternative to the Exos Pro 55 is the REI Co-op Flash Air 50, which also has back padding that reminds us of more conventional packs but features a very light main pack body. The main difference between the two is that the Flash Air 50 is a roll-top.
Going lighter often means starting out from the trailhead with simpler gear and a little more knowledge on how to best use what you've brought along. For discriminating ultralight tastes, we have the The Cutaway from Nashville Pack, an expert's pack with very impressive stats. This 40-liter pack keeps its weight-to-volume ratio low by forgoing an internal frame and padding. “Without padding, I recommend packing this rig strategically so that nothing pokes you in the back,” says our tester. If you've dialed in your sleeping system and shelter setup, then The Cutaway could be the cherry on top of your ultimate UL kit.
SPECIFICATIONS
Weight per Liter (Full Pack)
0.40 oz/L
Measured Weight
22.0 oz
Advertised Volume
40 L
Measured Volume (Main Compartment)
43 L
Stripped Weight
17.3 oz
The Cutaway's shoulder strap system and external pockets are both ahead of the game and good enough reasons to suggest this pack to almost anyone. However, frameless packs can be a bit polarizing – not everyone's back and shoulders are going to agree with the lack of traditional support. “I usually rig up my foam sleeping pad to the back of this pack for extra comfort,” our lead tester shares. “But it is one more step I need to do before I get going for the day.” For a little more convenience, consider the Zpacks Arc Haul Ultra as a suitable alternative. It's another excellent pack targeted at skilled long haulers, just with a frame design that helps move some of the load off your shoulders and keeps air flowing across your back. But if you're already sold on the idea of the frameless pack, then look no further than The Cutaway.
Modular design allows you to dial in the pack for different trips
Excellent running vest-style shoulder straps with ample pockets
Ultra fabric is ounce-for-ounce, one of the toughest pack materials
Tapered center mesh pocket retains gear
CONS
Not the most comfortable carry for heavier loads
Limited external daisy chains or tie-off points,
More expensive than many other similar packs
There are many details we love about the Black Diamond Beta Light 45, from its tough yet lightweight Ultra 200 fabric to its running vest-inspired shoulder straps (with all those easy-to-access pockets!) But what surprised and delighted us the most was just how versatile and modular the pack design was for different trips. We could use all of the built-in features for heavier loads or strip them off when going fast and light – the latter being what this pack is best for. This pack only weighs 19 ounces when fully stripped, yet still has 40 liters of internal capacity and more than 10 liters of carrying capacity externally. “For newer ultralight backpackers, this pack offers lots of options to work with while dialing in your preferences and perfecting your systems,” notes our lead tester. “This is a pack that'll grow with the owner.”
SPECIFICATIONS
Weight per Liter (Full Pack)
0.70 oz/L
Measured Weight
31.7 oz
Advertised Volume
45 L
Measured Volume (Main Compartment)
40 L
Stripped Weight
19.0 oz
Unfortunately, this Transformer of a pack isn't great at carrying heavy loads, and we struggled to carry much more than 35 lbs. The main problem is that the Beta Light 45 doesn't transfer pack weight to the hip belt as well as other packs we tested. The vest-style shoulder straps and sternum strap have a bit of stretch to them, which is great for moving quickly (and even running) but not so great for carrying out a seven-day load. Our lead tester adds some insight: “This pack may appeal to those who like how their running vests and day packs feel and want to capture that in their Ultralight pack.” If you'd rather trade a bit of versatility for an even lighter pack, the Mountain Laurel Designs Exodus 55L is our top suggestion. But for high mileage, long days, and lighter loads, the BD Beta Light 45 will support your performance-oriented goals.
The banana-shaped right front pocket on the Beta Light 45 securely fits our phone for easy access to messaging and navigation.
The Mountain Laurel Designs Exodus 55L is what one may imagine — both the good and the bad — of what ultralight backpacks are all about. It has advanced composite materials whose weight rivals that of tissue paper, with slimmed-down features, minimal pockets, a cool name, and a hot price tag to match. There's a lot to unpack concerning the Exodus, but if you're an advanced hiker already possessing a streamlined kit and looking for the best weight-to-volume value on the market, the Exodus is made for you. “The Exodus may be exactly what you're looking for, but it could take a few trips out to come to that conclusion,” admits our lead tester.
SPECIFICATIONS
Weight per Liter (Full Pack)
0.30 oz/L
Measured Weight
16.4 oz
Advertised Volume
55 L
Measured Volume (Main Compartment)
47 L
Stripped Weight
15.1 oz
If you're not yet that advanced of a backpacker and your entire carry weight is more than 20 pounds, then the Exodus won't support you as you gain the requisite experience to be the next “Flyin'” Brian, “Anish” Anderson, or Jeff “Legend”. The big spoiler to the Exodus's incredible weight-to-volume ratio is that it skimps out on back padding, an internal frame, as well as other niceties like hip belt pockets, making you figure those details out yourself using clever packing and repurposing gear. “The Exodus is made to support you moving fast by being light, but you'll need to bring along your experience too,” mentions our lead tester. If that's too much of a puzzle to solve on top of all the other logistics of a big-thru hike, consider another ultralight backpack like the Gossamer Gear Mariposa 60 that better supports your adventure, both literally and figuratively.
The Exodus 55L (seen here with additional accessories) is a finely-tuned long trail crusher, but make sure it's the right amount of pack for your experience and goals.
Credit: Justin Simoni
Compare Product Specifications
Specifications
Gossamer Gear Mariposa 60
Gossamer Gear Gorilla 50
Osprey Exos Pro 55
Zpacks Arc Haul Ultra
Black Diamond Beta Light 45
Hyperlite Mountain Gear Unbound 40
Nashville Pack The Cutaway
Durston Kakwa 55
Hyperlite Mountain Gear Porter 55
Six Moon Designs Swift V
Pa'lante V2
Adventure Equipment Ohm 2.0
Adventure Equipment Ultra Circuit
Granite Gear Crown3 60
Hyperlite Mountain Gear Southwest 55
REI Co-op Flash Air 50
Adventure Equipment Circuit 68
LiteAF Multi-Day 35L Frameless
Adventure Equipment CDT
Mountain Laurel Designs Exodus 55L
Homiee 50L with Rain Cover
Awards
Best Overall Ultralight Backpack
Best Bang For Your Buck
Best Full-Featured UL Pack
Best for Long Distance Thru-Hikes
Best Pack for Expert Ultralighters
Best High-Capacity Pack
Measured Weight
34.3 oz
32 oz
33.2 oz
21.8 oz
31.7 oz
34.6 oz
22.0 oz
29.8 oz
31.5 oz
38.0 oz
18.6 oz
31.4 oz
35.9 oz
31.5 oz
33.8 oz
32.0 oz
40.0 oz
18.9 oz
31.5 oz
16.4 oz
31.7 oz
Weight per Liter (Full Pack)
0.57 oz/L
0.64 oz/L
0.60 oz/L
0.44 oz/L
0.70 oz/L
0.87 oz/L
0.40 oz/L
0.49 oz/L
0.57 oz/L
0.76 0z/L
0.50 oz/L
0.50 oz/L
0.53 oz/L
0.53 oz/L
0.52 oz/L
0.64 oz/L
0.59 oz/L
0.54 oz/L
0.58 oz/L
0.30 oz/L
0.63 oz/L
Advertised Volume
60 L
50 L
55 L
50 L
45 L
49 L
40 L
61 L
55 L
50 L
37 L
63 L
68 L
60 L
64.8 L
50 L
68 L
35 L
54 L
55 L
50 L
Measured Volume (Main Compartment)
54 L
45 L
46 L
35 L
40 L
35 L
43 L
45 L
35 L
55 L
35 L
41 L
37 L
40 L
49 L
45 L
46 L
40 L
37 L
47 L
32 L
Stripped Weight
18.0 oz
16.2 oz
30.4 oz
17.9 oz
19.0 oz
26.0 oz
17.3 oz
26.2 oz
31.5 oz
27.8 oz
18.6 oz
20.4 oz
24.2 oz
22.1 oz
30.2 oz
27.0 oz
37.5 oz
16.3 oz
22.1 oz
15.1 oz
29.8 oz
Organization Compartments
Top flat zippered pocket, three total side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Top flat zippered pocket, side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Lid, mesh side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Main compartment, center pocket, side pockets
Side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Side pockets, center pocket, dual zippered pockets on hip belt, bottom stash pocket, main compartment
Main compartment, center pocket, running vest-style pockets, back-entry bottom stash pocket
Shoulder strap pockets, side pockets, zippered stash pocket on side pocket, center pocket, dual zippered pockets on hip belt, main compartment
Dual zippered pockets on hip belt, main compartment
Main compartment, stretchy side pockets, stretchy center pocket, dual hip belt pockets, running vest pockets, internal water resevoir pocket
Side pockets, center pocket, bottom stash pocket, main compartment
Side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Lid, side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Side pockets, center pocket, dual zippered pockets on hip belt, shoulder strap phone pocket, main compartment
Side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Main compartment, stretchy side pockets, stretchy center pocket, shoulder strap pockets
Side pockets, center pocket, dual zippered pockets on hip belt, main compartment
Optional shoulder strap pockets, side pockets, center pocket, optional dual zippered pockets on hip belt, main compartment
Non-removable lid, mesh side pockets, center pocket, dual zippered pockets on hip belt, sleeping bag compartment
Hydration Compatible
Yes
Yes
Yes
No
Yes
No
No
Yes
No
Yes
No
Yes
No
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Side Pocket 700ml Smartwater Capacity
3
3
5
2
5
5
Continuous wraparound pocket
4
N/A
2
3
N/A
4
5
2
3
N/A
3
2
2
1
Single Hip Belt Pocket Capacity
6 Clif Bars
6 Clif Bars
4 Clif Bars
N/A
5 Clif Bars
6 Clif Bars
N/A
10 Clif Bars
6 Clif Bars
8 Clif Bars
N/A
8 Clif Bars
5 Clif Bars
5 Clif Bars
5 Clif Bars
5 Clif Bars
2 Clif Bars
N/A
5 Clif Bars
6 Clif Bars
3 Clif Bars
Removable Frame and Hip Belt
Yes
Yes
No
No
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
No
No
Sternum Strap Whistle
Yes
Yes
Yes
No
No
Yes
No
No
Yes
No
Yes
No
No
No
Yes
Yes
No
No
No
Yes
Yes
BearVault BV500 Compatibility
Good
OK
Good
OK
Good
OK
OK
OK
OK
Good
Good
OK
Good
Good
Good
Good
Good
OK
OK
Good
No
Sizes Available
Torso: S, M, L
Hip Belt: S/M Curved (w/ S torso), M Straight (w/ M and L torso); other hip belts sold separately
Torso: S, M, L
Hip Belt: S/M Curved (w/ S torso), M Straight (w/ M and L torso); other hip belts sold separately
Torso: S/M, L/XL
Torso: Short, Medium, Tall,
Hip Belt: S, M, L, XL
Torso: XS, S, M, L
Torso: S, M, L, Tall
Hip Belt: M (S & L sold separately)
Torso: 16', 18", 20"
Hip Belt: S (28"-38"), M (32"-42"), L (26"-48")
Should Straps: 16", 17.5", 19", 20.5"
Torso: S, M, L
Torso: S, M, L, Tall
Torso: Adjustable, 4 lengths
Hip Belt: S, M, L
Shoulder Straps: Vest, Classic Shoulder, S-Curve Shoulder
Torso: 16", 19"
Torso: S, M, L, XL
Hip Belt: XS, S, M, L, XL, XXL
Torso: S, M, L, XL
Hip Belt: XS, S, M, L, XL, XXL
Torso: Short, Regular, Long
Hip Belt: Adjustable
Torso: S, M, L, Tall
Torso: S, M, L
Torso: S, M, L, XL
Hip Belt: XS, S, M, L, XL, XXL
Torso: S, M, L
Torso: S, M, L, XL
Hip Belt: XS, S, M, L, XL, XXL
Torso: M, L, XL
Torso: One size
Frame Type
Removable SitLight foam pad / removable stay
Removable SitLight foam pad / removable stay
3.5 mm powder-coated LightWire frame
Curved carbon fiber stays
2 removable stays, thin foam padding
1 removable aluminum stay, embedded, non-removable foam pad
None
Removable hollow aluminum U-frame and removable foam back padding
Dyneema hardline, removable aluminum stays, padded back panel
Delrin hoop stay frame
None
Simple frame - 1.2 oz carbon fiber / Delrin active suspension hoop
Foam pad, carbon fiber suspension hoop, and single aluminum stay
Current Mark 3 compression molded PE, optional U-shaped aluminum stay
2 removable aluminum stays
Spring steel shaped frame, non=removable foam padded back
Simple frame - 1.2 oz carbon fiber / Delrin active suspension hoop
None
Removable foam pad
None
None
Fabric
100D & 210D recycled Robic nylon
70D & 100D recycled Robic nylon
NanoFly: 100D nylon x 200D UHMWPE ripstop
Main body: Ultra 100X
Center pocket: Nylon mesh
Side pocket: Ultra 100X
Main body: 100D Robic Dynatec
Pockets: Ultra Stretch
ULA 400 Robic nylon
Ecopak UltraWeave 200D
420D lattice nylon & 420D plain nylon
The burning in our legs from the incredible climbs is worth it for the views!
Credit: Justin Simoni
How We Tested
Over the past eleven years, our testing process has always begun with deep research into the market to see what's out there. After we make our selection, we purchase all the products at retail prices to eliminate bias from our reviews. Our ultralight backpack testing protocol consists of both lab testing and miles upon miles on the trails. We independently verify weight and volume measurements. Then, we take it a step further by scoring packs based on their weight per unit volume, allowing us to compare different volumes fairly. On-trail testing included trips such as 260 winter miles on the AT, five segments on the Colorado Trail, The “Argentine Pine” alt on the CDT, and completing the arduous Sangre de Cristo Range Traverse in Colorado. We spent time in Patagonia, the Continental Divide Trail, and the Sierra High Country. Additionally, we made direct comparisons using 15 and 30-pound weights for shorter test laps around our local trails in Boulder, CO.
Our ultralight backpack testing is divided into four different metrics:
Comfort (40% of overall score weighting)
Ease of Use (25% weighting)
Weight-to-Volume Ratio (20% weighting)
Adjustability (15% weighting)
Why Trust GearLab
This review is the result of the combined efforts of several GearLab ultralight experts. Justin Simoni has led the review for the past few seasons. He lends his deep knowledge and vast experience gained from his time in the Colorado backcountry, as well as guiding in California and Alaska. Simoni has done fast-and-light missions following the true ridges of the Continental Divide, the Sangre de Cristo Range, and the Mosquito-Tenmile Range. With no external support, he has summited all the Colorado 14ers and Centennials in two separate years. He can be heard quietly musing about giving an unsupported FKT (fastest known time) of the Colorado Trail another go after his daily high-elevation-gain trail runs. Jane Jackson and Brandon Lampley bring to the table a wealth of related experience. For 200+ days a year, you can find Jane outside using and testing gear. With years spent working and playing in the Yosemite backcountry, the Tetons, and the Wind River Range, as well as trips taken to the Alaska Range, the Himalayas, and Patagonia, she has spent plenty of time under the burden of a heavy pack. Brandon has hiked both the Pacific Crest Trail and the Appalachian Trail, essentially back-to-back, with only four months off in between. He also has first ascents to his name in the Indian Himalayas and has summited Denali and Ama Dablam.
We took all these packs on a variety of outdoor adventures to help you find the best pack for you.
Analysis and Test Results
Over the past decade, we've tested hundreds of backpacks of all styles. The products we've included in this review represent the cutting edge in ultralight technology. If you're looking for larger frames and luxury padded waistbelts, look elsewhere; the packs in this review hardly resemble a traditional backpacking pack. Many exciting small brands have popped up in this category of outdoor gear over the past few years, as well as strong options from larger brands. We've had fun assessing their latest products. Here, we evaluate the top products available for multi-month thru-hiking adventures and shorter alpine trips focused on fast and light backcountry travel.
Worse Value
Better Value
What's the Best Value?
When making an outdoor gear purchase, we often trade off one thing for another, and no one understands trade-offs better than an ultralight enthusiast. We all spend too much time “weighing” our options. Bringing a slightly thicker sleeping pad can mean foregoing powdered milk in the coffee- decisions, decisions. However, ultralight packs continue to get better and more comfortable as time passes.
Side pockets are easy to access and a perfect place to stash on-the-go snacks. Well-designed features that work are one of the big reasons why we think the Hyperlite Mountain Gear Unbound 40 delivers good on value.
Credit: Justin Simoni
The Gossamer Gear Gorilla 50 offers very impressive comfort and versatility for a reasonable price. The Gossamer Gear Mariposa 60 isn't much more expensive but is our favorite all-around ultralight backpack. Alternatively, the ULA Ultra Circuit is more expensive but is also made of more durable materials designed to last for a long time through trying conditions. The Durston Kakwa 55 is one of our lineup's most dialed-in ultralight packs at an excellent value.
Not only is the Gorilla 50 highly functional, its value shines when you compare its price to many of the other overall high-scoring ultralight packs we tested.
Credit: Justin Simoni
We found one of the least expensive packs in our lineup, the Homiee 50L with Rain Cover, just didn't deliver on the level of performance we'd expect from a high-value ultralight pack. This pack might not be a great choice except for taking on the most casual trips or having it as a backup pack in the trunk of your car that you can grab to take a quick trip.
Unfortunately, we found many of the features of the Homiee 50L with Rain Cover too lacking for serious backpacking, but it does make a reasonable option for casual overnights.
Comfort
Of course, we all want an ultralight pack to be featherlight, but it must carry our load comfortably to be worth it. For each of these packs, we judged load-carrying comfort for two loads: 15 and 30 pounds. We then averaged each pack's performance in both categories to generate our carrying comfort score.
Fifteen pounds is a perfect comparison weight for ultralight hikers on a short trip. Thirty pounds is a fair comparison weight for lightweight hikers on shorter trips, ultralight hikers carrying a week's worth of food, or those brave enough to travel in the winter. While some packs can be stripped of their frame and waist belt, our evaluation of “great, good, or poor” for carrying 15 and 30 pounds is with the frame and waist belt in use, as these features add significantly to the comfort of carrying a pack. We only recommend stripping down a pack completely when carrying 12 pounds (or less) in total weight.
The Most Comfortable Packs by Weight
To simplify our findings for load-carrying comfort even further, we've broken down some of our award winners' niches as far as load-carrying comfort goes:
Best for 10-20 lb loads: Mountain Laurel Designs Exodus 55
Best for 15-25 lb loads: Gossamer Gear Gorilla and Mariposa
Best for 35+ lb loads: Six Moon Designs Swift V, Hyperlite Mountain Gear Unbound 40, and Hyperlite Mountain Gear Southwest 55
The Gossamer Gear Mariposa 60 and Gorilla 50 are two of the most comfortable packs we've ever tested. The main difference is that the Mariposa offers a bit more internal capacity for only a tiny weight penalty. With hip belts attached and back pads on, these packs are well-balanced and secure to carry. For carrying loads under twelve pounds, they are also some of the easiest packs to strip off their frame and waist belts without sacrificing any amount of comfort.
The tensioned carbon rods and mesh backing of the Zpacks Arc Haul Ultra help to support your load while still letting air flow around your back.
Credit: Justin Simoni
The Osprey Exos Pro 55 is nearly as comfortable as either of the Gossamer Gear packs, but for different reasons. Its tensioned mesh back panel and wrap-around, non-removable hip belt help to distribute weight far better than most other solutions in the ultralight world. A similar philosophy is employed on the svelte Zpacks Arc Haul Ultra. Adjustable, tensioned carbon rods bow the back panel to conform to the shape of your body while at the same time providing a sprung, hammock-like surface to improve airflow.
In addition to offering a ton of up-front storage space, the Swift V's running vest-inspired shoulder straps hug your body for a more secure carry.
Credit: Justin Simoni
The running vest-inspired design of the Six Moon Designs Swift V does an excellent job of pulling the pack close to your body to reduce any bounce. The removable, internal hoop stay and wide hip belt also provide enough support and rigidity to carry heavier loads. The pack is designed so that only the center column rests against your own back, helping maximize airflow. If running vest-inspired packs are attractive, the Black Diamond Beta Light 45 and Nashville Pack The Cutaway also offer some serious comfort with their own take on this design. Though unlike the other two, The Cutaway is a frameless pack, so overall comfort is entirely dependent on how you pack your rig.
The padding throughout the lumbar region of the Unbound 40 makes this pack incredibly comfortable, and the belt is still removable to shave weight or swap for a different size (which are sold separately).
Credit: Justin Simoni
The Hyperlite Mountain Gear Unbound 40 also scored well, thanks to its cushy built-in back padding, which helps keep your gear from poking you with every step. The single curved back stay is removable to tweak the shape to better suit the curvature of your back or if you want to take it out completely. If you're looking for even more internal storage with a similarly comfortable design, look seriously at its brethren, the Hyperlite Porter 55. Despite all of their other features, it's interesting that neither of these Hyperlite packs has load lifters. Load lifters are often a nice addition to larger packs to adjust how the pack weight is distributed – if this is a point you're unwilling to compromise on, the REI Co-op Flash Air 50 has some of the best of any pack we tested.
Simple yet effective load lifters like what's found on the REI Co-op Flash Air 50 can help adjust how the pack sits on your upper back, making it easy to dial in the fit even on the go.
Credit: Justin Simoni
Ease of Use
How easy is it to use the features of the pack? Similar to comfort, what's the point of a specialized pack if you need an advanced degree in spatial awareness to use it? We used every pocket repeatedly to see how conveniently they were located, how easily they were accessed with and without removing the pack, and how versatile they were for different types of trips and different styles of packing.
The Osprey Exos Pro 55 really delivers every time we really need to get up and get going. The Exos Pro is very “Batteries Included,” having many of the features we like already incorporated, all for only a small weight penalty. If you're transitioning to ultralight from a more conventional backpack, this pack makes the transition utterly painless.
We love the side pockets on the Osprey Exos Pro, which are easily accessible even while wearing the pack.
Credit: Justin Simoni
The one-two punch of the Gossamer Gear Gorilla and Gossamer Gear Mariposa also get high honors for ease of use. Both are intuitively designed, making it easy to just throw them on your back, yet both have the features we like to see in more advanced packs. Standout details include the voluminous center pocket – like every stitch of clothing we'd need from sun-up to sun-down – which keeps us from having to open up the main compartment to rummage around for a jacket.
The Gossamer Gear Gorilla 50 delivers a ton of value for the features it offers, and was our choice for a particularly adventurous alternative on the CDT through the hinterlands of Colorado.
Credit: Justin Simoni
Not to be totally outdone by the packs above, the REI Co-op Flash Air 50 is also a great option for folks transitioning to an ultralight pack. The Flash Air takes a lot of design cues from its more conventional cousin, the REI Co-op Flash 55, including its particularly deep side pockets. The Hyperlite Mountain Gear Unbound 40 seems to take the opposite approach, borrowing some of the best features found in a spectrum of standout UL packs, then assembling those features into an all-star pack. We loved the easy-to-access side pockets, bottom stash pocket, and of course, its stealthy, DCH pack material.
The side pockets of the Unbound 40 are some of our favorites because they're accessible to us while on the move.
Credit: Justin Simoni
On the opposite side of the ultralight spectrum is the Hyperlite 3400 Porter. This pack is designed as a modular system that you can build up like Lego blocks. Need more carrying capacity? Just lash an accessory pack to the exterior daisy chains. The Porter is a super burly pack with utmost flexibility. The Durston Kakwa 55 also has some well-thought-out features and pockets that are a joy to use. We particularly like the zippered stash pocket found within one of the side pockets to allow us to securely keep very important items, like keys and cards.
The Durston Kakwa 55 comes ready out of the box to help support you on your next long distance hike.
Credit: Justin Simoni
The ULA Ohm 2.0 can fit an impressive eight Clif Bars into each of its hip pockets. The Granite Gear Crown3 60 has a lid with a brain for those folks who love that feature. It can also fit five Smartwater bottles in each of its side pockets. The ULA Ultra Circuit is also impressive, though it holds just four 700-milliliter Smartwater bottles in each of its side pockets. The Gossamer Gear Gorilla and Mariposa, Osprey Exos Pro, Hyperlite Porter, Southwest, Unbound 40, REI Co-op Flash Air 50, Homiee 50L with Rain Cover, Pa'lante V2 and Mountain Laurel Exodus all have whistles attached to their sternum straps.
The Pa'lante V2 includes a built-in emergency whistle on its sternum strap.
Weight-to-Volume Ratio
The weight-to-volume ratio is a measurement used to compare packs of differing volumes. This metric starts with objective measurements: how much does this pack weigh relative to the volume it carries? We measured the weight of each model on our digital scale and the volume of the main compartment.
We measured internal pack volume, as well as the volume of the main exterior pockets. This gives us a normalized way to compare packs from different manufacturers using the same rules. Most pack makers are honest with the volume numbers they advertise. However, pack capacity, in liters, is sometimes different than the number used in the product name. So we suggest buyers look a little more closely into the specifications of the packs to make sure they understand how manufacturers are calculating their volume numbers – you'll often see internal and external volumes advertised.
The Hyperlite Mountain Gear Southwest 55 was found to have an internal volume of 49 liters -- one of the most voluminous packs we measured.
Credit: Justin Simoni
How Do We Measure Volume?
To measure the internal volume of a backpack, we use hundreds of ping pong balls, which are an easy-to-source substitute for the smaller-diameter 20mm balls used in the standardized industry test. We stuff as many as possible into the main compartment, ensuring that we can still securely close the pack. We then use a trash can-turned-giant graduated cylinder to measure the volume of ping pong balls. The larger-diameter ping pong balls may not be quite as accurate as the standarized test, but we've found this test is a worthy means of verifying manufacturer's claims. The ping pong ball test is especially useful for comparing products from different manufacturers, as everyone seems to measure their packs in a different way. We've run this test for years, and we're confident our system of measurement is precise to +/- 3 liters.
We measured the Durston Kakwa 55 as having approx. 45L of internal storage in the main compartment when stuffed with ping pong balls to the point of bursting, then rolled down and secured.
Credit: Justin Simoni
For external pockets, we'll use a variety of common items to get a feel of their carrying capacity. Oftentimes external pockets are open-ended, so the exact volume is difficult to report, as what constitutes the pocket being “full” is subjective For center and side pockets, we normally use smartwarter bottles; for hip belt pockets, we utilize the Clif Bar.
We utilize smartwater bottles for external side, center, and bottom pockets, as well as Clif Bars for hip belt pockets, to give you a visual idea on the carrying capacity of these pockets.
But numbers only tell part of the story. We also consider what each pack's weight gets you in terms of durability. After all, a superlight pack that tears the first time you scrape it across a boulder isn't worth all that much. We scrutinized and compared fabrics, seams, and components like zippers and buckles. We researched common complaints for each pack to see if we had the same sorts of issues during our weeks spent in the backcountry. By pulling both objective measurements and subjective observations by our expert testing team, we created a complete picture of the value each pack offers, corresponding with its weight-to-volume ratio.
Ping pong balls ruled the roost when measuring the internal volume.
Credit: Justin Simoni
When we calculated the weight-to-volume ratio to compare each pack directly, regardless of volume, we got a comparable idea of how light these packs really are. All the packs in the ultralight category fared extremely well when looking at their weight-to-volume ratios, but there certainly are some standouts.
If you're moving fast through harsh terrain, ULA packs, like the Ultra Circuit, are made entirely of Ultra fabrics, which makes them super durable and more water resistant.
Credit: Justin Simoni
The Challenge Outdoor Ultra family of composite materials comes up often when we look at packs with excellent weight-to-volume ratios, as these materials are incredibly durable while maintaining low weight. They're also very water resistant, which means you may think about setting off from the trailhead without a pack liner, saving even more weight.
The large pack volume of the Mountain Laurel Exodus is attained with an extra-long roll top. Given the manufacturer's low 20-pound load limit, you may find it difficult to fully pack this main compartment.
Credit: Justin Simoni
Top honors for weight-to-volume go to the Mountain Laurel Exodus 55, with its seriously low weight-to-volume ratio of just 0.3 ounces per liter! It's built as a fast-and-light pack for expert ultralighters that practically dares you to break long trail hiking speed records. The Exodus has minimal features, smaller exterior pockets, and a large main pack compartment. The lightweight (3.5 ounces per square yard) Ultra 200D fabric is tough and expertly sewn to create the pack's main compartment.
The incredible Ultra 100X material of the Zpacks Arc Haul Ultra is some of the thinnest and lightest around, especially for how strong it is.
Credit: Justin Simoni
Perhaps going a step further, the Zpacks Arc Haul Ultra opts for the even thinner Ultra 100X fabric for the main body and a carbon fiber frame. This delivers a pack with 35 liters of internal capacity, along with a giant center mesh pocket, at an incredible 0.44 ounces per liter. But the Arc Haul Ultra isn't alone; packs that stand out for their Ultra materials abound in our lineup. The full Ultra 200 X Durston Kakwa 55 comes in at a very respectable 0.42 oz/L. The more abrasion-resistant Ultra 400x bodies on the Ultralight Adventure Equipment Ultra Circuit and Black Diamond Beta Light 45 come in at 0.53 oz/L and 0.70 oz/L, respectively. These slightly higher weights also tend to correspond with additional features.
Stripped of many of its optional accessories and by rolling the roll top down tightly, the Black Diamond Beta Light 45 makes a fairly good day pack.
Credit: Drew Crittenden
But Ultra isn't the only game in town. If you're looking to save a little weight and money on your next ultralight pack purchase, there are some other compelling fabrics out there. The 18.6 oz Pa'lante V2 is made with a strong, lightweight, and cost-effective Nylon 210D UHMWPE Gridstop. This material boasts a 0.5 ounces per liter weight-to-volume ratio (and that's only counting the pack's internal capacity!. Side, center, and a bottom stash pocket carry even more gear. The LiteAF Multi-Day 35L Frameless, made of a similar 100D Robic Dynatec fabric, boasts a competitive ratio of 0.54 oz/L.
The thin yet tough 210d UHMWPE gridstop used in the Pa'lante V2 is plenty strong for long distance duties.
With a weight-to-volume ratio of 0.55 ounces per liter, we also hold the Nashville Pack The Cutaway in high regard, namely because the 21-ounce pack weighs significantly less than most of the other 40-liter packs in our lineup. This is a highly customizable pack and we opted for the default Venom Gridstop ECO pack material — similar to the Pa'lante. The Granite Crown3 has a similar ratio of 0.53 oz/L and is a particularly great choice if you're shopping on more of a budget. You can even cut down on some of the included features to save additional weight.
The Granite Crown3 has a ton of internal storage in a lightweight package.
Credit: Justin Simoni
Adjustability
Adjustability tests how well a pack conforms to your body, adapts to different adventures, and carries the usual suspects of backpacking gear. We asked ourselves: Is this pack working with or against us in the adventures we want to bring it along for? We also considered the sizing and customization options that were available during the ordering process.
Ultralight backpacks used to have a sour reputation of not accommodating a wide range of body types. More often than not, you'd need to try out a few packs and see which one fits you best. But recently, that stigma has changed for the better, with pack makers coming up with innovative ways to make their packs more adjustable, making their packs more accessible and more comfortable than ever before.
The shoulder straps on the Granite Virga3 accommodate an incredible range of both torso height and width.
Credit: Justin Simoni
The Granite Gear Crown3 60 features a hyper-adjustable hip belt that can be extended to cover multiple conventional belt sizes. This belt can also be paired with the Crown3's removable lid to become a hip pack for day trips away from base camp.
Nashville Pack's The Cutaway features a clever shoulder strap attachment system that allows you to swap different lengths, as well as adjust the width and angle at which the straps are attached to the pack.
Nashville Pack offers an impressive list of options to customize The Cutaway before it even gets shipped to you. Pick the torso length of the pack, as well as the perfect shoulder strap length to accommodate your own body. (Don't worry, Nashville Pack provides clear instructions to help you make these decisions.) Once you have the pack in hand, you can choose where to attach the shoulder straps to accommodate wide and narrow shoulders, and you even have the option to switch them out for different shoulder straps in the future.
Torso length is easily adjustable on the Six Moon Designs Swift V, helped in part by the optional tool included with the pack.
Credit: Justin Simoni
Similarly, Six Moon Designs offers three different shoulder strap styles for the Swift V: running vest, conventional, and S-curve. We chose to test the Swift V with the running vest-style shoulder straps because they offer additional large pockets and an excellent fit. You can adjust the pack's torso length to dial in the perfect fit or even easily adjust it for a friend if you lend it out. Torso length adjustability is also a core feature of the Osprey Exos Pro 55, which is nice considering the mesh back panel.
The built in torso length adjustment of the Osprey Exos Pro 55 is one of its best features.
Credit: Justin Simoni
Many packs are modular in design, allowing you to forgo many of the optional elements. This gives you the superpower to pair the pack down for weight savings, make it more appropriate for shorter trips, and allow you to grow with the pack as your own ultralight backpacking experience matures. The Gossamer Gear Mariposa and Gossamer Gear Gorilla both scored highly for adjustability, with an incredible amount of modularity in both of their similar designs, which allows them to be worn comfortably — depending on load — with or without their back padding, internal frame, or hip belt. Both of these packs can also be purchased with “mix and match” hip belts, allowing you to order your perfect combination of sizes. This customization is also available for all the ULA packs we tested (the Ohm 2.0, Ultra Circuit, Circuit, and the Ultralight Adventure Equipment CDT).
Both the Gorilla and Mariposa have removable back padding, internal frame, and hip belt.
Both the Black Diamond Beta Light 45 and Hyperlite Mountain Gear Unbound 40 are also designed to be stripped of their hip belt, internal stays, and compression straps for very fast and light adventures when carrying lighter loads. The Beta Light can also have its minimalist back padding removed.
Both the Hyperlite Mountain Gear Unbound 40 and Black Diamond Beta Light 45 are designed to be modular, so you can take off parts for a lighter load at the expense of carrying weight limit and comfort.
The Hyperlite Porter adjusts to suit your needs in a very different way, featuring a plethora of daisy-chained webbing on its exterior for you to lash on almost anything you can think of. Its load limit is rated quite high, so feel free to pile on the gear and accessories.
Where will your perfect ultralight backpack take you?
Credit: Justin Simoni
Conclusion
We hope the information in this review sparks an interest in the ultralight world. If all the gear required feels overwhelming, simply getting a lightweight pack is a wonderful place to start. A light pack automatically jumpstarts the transition toward lightening up the rest of your kit. The packs in this review range from extremely slimmed down to more comfy options for those unwilling to part with the standard backcountry creature comforts. Our testers have worn loads of different packs within and outside the ultralight world, bringing a breadth of experience to help guide you toward the pack that is right for you.
If you'd rather trade a little extra weight for more comfort, larger carrying capacity, and extra organizational features, check out our reviews of backpacking backpacks or backpacking packs for women.