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Ready to join the ultralight revolution? Over the past decade, our thru-hiking experts have tested more than 50 of the best ultralight backpacks around. In this latest iteration, we bring you the top 23 ultralight backpacks on the market. To put these packs to the test, we've 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. We logged hundreds of trail miles to assess performance based on our rigorous testing metrics, including weight-to-volume ratio, carrying comfort, adjustability, and how easy it is to use all the features of the pack. Each year, the ultralight world grows and becomes increasingly innovative and competitive. This review highlights budget-friendly models, our top-ranked packs, as well as niche products for veteran hikers.
If you're looking to shave a few ounces (or pounds) from your pack, check out our other reviews for the best in ultralight gear. If you're willing to carry a little extra weight for more comfort, larger carrying capacity, and extra organizational features, check out our reviews of the best backpacking backpacks or best women's backpacking backpacks.
Editor's Note: We updated this review of ultralight backpacks on September 6, 2024, to include more packs from Zpacks, Six Moon Designs, Nashville Pack, and LiteAF.
Abrasion-resistant Robic nylon, comfortable, well-designed pockets, carries both light and heavy loads well
Lightweight, carries light and medium loads well, adaptable, perfect feature set, more durable than most
Tons of external storage with different pockets, durable and water-resistant DCF pack material, comfortable yet minimal padding and vertical stay, removable hip belt
Modular design, running vest-style shoulder straps, rough and light Ultra 200 pack fabric, voluminous center pocket
Lightweight yet tough and water-resistant pack material, unique curved frame improves ventilation, built-in torso height adjustment, excellent volume and features for its weight
Cons
Large capacity makes it less versatile
A little small for a bear canister
Durability comes at a cost of additional weight, lacks load lifters
Limited external lash points, pricier than other options, not as comfortable to carry the heaviest loads
Very expensive, frame system doesn't fit everyone well
Bottom Line
This pack wowed us with its perfect set of features, comfortable design, and impressively large carrying capacity
Delivers a perfect set of features, plenty of pockets, comfortable straps, and carries well, all at an affordable price
For those seeking a pack to support their cross-country thru-hikes with tons of external storage space, excellent weather resistance, and famous durability
A pack that's clearly made to make you feel like you could run to the next mountain range over yonder without breaking a sweat
It's hard to beat this pack's innovative curved frame design for enhanced airflow across your back
Total Weight: 32.6 oz | Weight-to-Volume Ratio: 0.54 oz/L
REASONS TO BUY
Comfortable with both light and heavy loads
Versatile
Great feature set
Well made
Fits bear canister
REASONS TO AVOID
Heavier than some
Once again, against relentless competition from other brands, the Gossamer Gear Mariposa 60 holds its place at the top of the fleet. This pack balances comfort with an unparalleled emphasis on lightweight design. Its feature set is thoughtful and useful but not overkill. It provides plenty of external carry options without feeling weighed down by superfluous bells and whistles. The Mariposa has our favorite stretchy center mesh pocket, 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. The fabrics used in its design are durable and lightweight; miles of bushwhacking and talus-crossing hardly left a scratch.
Marketed as a 60-liter pack, the Mariposa can carry up to 64 liters when stuffed to the brim. 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 model in our lineup, though its 32.6-ounce total weight and 0.54-ounce per liter weight-to-volume ratio are impressive. Plus, its slightly heavier weight added a level of comfort that couldn't be beaten. If you're looking to go much lighter, the Mountain Laurel Designs Exodus 55L is about half the weight. It offers a great weight-to-volume ratio but will cost you in comfort.
Total Weight: 31.1 oz | Weight-to-Volume Ratio: 0.62 oz/L
REASONS TO BUY
Tough but light Robic nylon construction
Can transform from a day hiker to a multi-day backpack
Great spread of features without compromising on weight
REASONS TO AVOID
Not as waterproof as other packs
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. It has great back padding, an internal aluminum frame, and an excellent hip belt. Those aren't the only reasons we love the Gorilla. Its voluminous external pockets swallow up gear so much that we rarely need to open the pack's main compartment until it's time to make camp. 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.
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. The top flap design of Gossamer Gear is unusual in our ultralight category, and you may prefer a rolltop. If you're especially rough on gear, the judicious use of mesh for the side and center pockets and holding the back padding in place may become untimely 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.
Nothing reminds us of the joy of sweet simplicity more than a good walk in the woods. The ultra comfortable Gorilla 50 let's you forget about your pack and focus on the trail.
Total Weight: 34.6 oz | Weight-to-Volume Ratio: 0.87 oz/L
REASONS TO 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
REASONS TO AVOID
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 DCF pack material means you don't have to worry about acute gear malfunction leaving you stranded several states in. 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. 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.
Comfort, carrying-ability, and convenience come at a cost, and for the Unbound 40, it's a few more ounces being registered 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 such carrying capacity yourself, it would be better to 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. 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.
Total Weight: 38 oz | Weight-to-Volume Ratio: 0.76 oz/L
REASONS TO BUY
Amazing amount of internal storage space
Running vest straps with pocket galore
Accessible hip belt pockets and side pockets
REASONS TO AVOID
Not as lightweight as other options
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 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.
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. 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.
Total Weight: 33.2 oz | Weight-to-Volume Ratio: 0.6 oz/L
REASONS TO BUY
Super well-thought-out design and features
Great suspension system
Excellent back ventilation
REASONS TO AVOID
Heavy for an ultralight pack
Lid top may be a turnoff for rolltop lovers
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 sincerely ultralight. Weight may be gone, but all the creature comforts that one expects from a backpack are not left on the cutting room floor. We especially loved the back suspension system that provided comfort against our pack load and gave a ton of air circulation our poor back so desperately craves.
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. 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 comfortability in the back and 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.
Total Weight: 21 oz | Weight-to-Volume Ratio: 0.53 oz/L
REASONS TO BUY
Many choices and accessories when ordering
Excellent weight-to-volume ratio
Surprisingly spacious internal capacity
REASONS TO AVOID
May not have enough features for some hikers
Lower carrying load limit
Frameless design can be harder to pack
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 – for the best experience, you'll want to pack this rig carefully so that nothing pokes you in the back. 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.
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. If that sounds like you, 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.
Total Weight: 31.68 oz | Weight-to-Volume Ratio: 0.70 oz/L
REASONS TO BUY
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
REASONS TO AVOID
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.
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. 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.
Total Weight: 16.4 oz | Weight-to-Volume Ratio: 0.30 oz/L
REASONS TO BUY
Featherlight and high-volume
Waterproof Ultra fabric
Excellent design and detail
REASONS TO AVOID
Very expensive
Low load limit, especially for volume
Fiddly to make it comfortable
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.
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. 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
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We snuck out to visit the Ice Lake Basin from Telluride while training up for the Colorado Trail with the Gossamer Gear Mariposa 60.
Credit: Justin Simoni
How We Test Ultralight Backpacks
Over the past ten 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 trail miles. We independently verify weight and volume measurements. 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, 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. 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 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. Justin Simoni lends his deep knowledge and vast experience to this review, gained from his time in the Colorado backcountry. Justin has done fast-and-light missions on the very ridge of the Continental Divide, the Sangre de Cristo Range, and the Mosquito-Tenmile Range. With no external support, he has summitted 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.
The ULA Ultra Circuit feels like a best friend on the trail, always supporting your long-distance outdoor adventures.
The Osprey Exos Pro 55 has an athletic fit and great breathability.
Cinch straps on the main pack body help add versatility for long thru-hikes as well as shorter day trips in the mountains.
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 the best 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.
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 the side pockets on this pack frustrating to both take out and put back in items while wearing it. We instead needed to stop, take off the pack and work with the pockets that way.
Small side pockets will only fit three smooshed Clif Bars.
Each side pocket is small, only fitting one smartwater bottle.
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.
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 and Hyperlite Mountain Gear Unbound 40
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 of the back 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 one-two punch of the Gossamer Gear Gorilla and Gossamer Gear Mariposa again get top honors in this metric. We found both models intuitive to use as soon as you throw them on your back, yet both have the features we like to see in more advanced packs. Standout details include the very voluminous center pocket that swallows up even large gear, like a bear canister.
The Gossamer Gear Gorilla 50 delivers a ton of value for the features it offers, and was our choice for a particularly adventurous route through then Sangre de Cristos.
Credit: Justin Simoni
Not to be outdone, the Osprey Exos Pro 55 also delivers when it comes to being a no-brainer to use. The Exos Pro is very “Batteries Included,” and for a small weight penalty, it just works without too much fiddling about. If you're transitioning to ultralight from a more conventional backpack, this pack makes the transition utterly painless. The REI Co-op Flash Air 50 will also feel at home from those coming from conventional packs.
We love the side pockets on the Osprey Exos Pro, which are easily accessible even while wearing the pack.
Credit: Justin Simoni
On the opposite side of the ultralight spectrum is the Hyperlite 3400 Porter, which in its own right is also easy to use but can grow with you like Lego blocks. Need more carrying capacity of any sort? Just lash on whatever you need. It has the utmost flexibility in carrying your gear while being super burly to boot. Its brethren, the Hyperlite Mountain Gear Unbound 40 include a wide variety of some of the best-designed external pockets that you won't find on the Porter, all ready to swallow up the gear you'd like to have close at hand without needing to open up the main compartment.
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
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 to go for 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, Mountainsmith Zerk 40, and Mountain Laurel Exodus all have whistles attached to their sternum straps.
The Mountainsmith Zerk has a whistle on the sternum strap and shoulder pockets that can easily fit these 700-milliliter Smartwater bottles.
Credit: Justin Simoni
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.
Pack volume was measured, 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. We were sometimes very surprised at how different the advertised total volume was from what we measured.
We measured the Durston Kakwa 55 as having approx. 40L of internal storage in the main compartment when the roll top is rolled 3x.
Credit: Justin Simoni
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.
We measured the internal volume of the Durston Kakwa 55 using ping pong balls to be around 40L.
The external center pocket of the Durston Kakwa 55 is a stretchy mesh that expands when you add gear. The mesh is useful for drying out wet clothes.
We measured the volume of the main compartments and all the extra pockets, too!
Ping pong balls ruled the roost when measuring the internal volume of various pockets of these packs.
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 faired 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 the fabric is incredibly durable while maintaining low weight. These materials are 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 money as well as weight on your next ultralight pack purchase, there are some other great options. The Gossamer Gear Murmur 36 Hyperlight is made of more conventional 30D Cordura & 70D Robic nylon yet still boasts an impressive weight-to-volume ratio of 0.35 ounces per liter. The LiteAF Multi-Day 35L Frameless, made of a similar 100D Robic Dynatec fabric, boasts a competitive ratio of 0.54 oz/L.
The Durston Kakwa 55 uses Ultra 200 fabric to make a very lightweight pack, especially considering the amount of internal space.
Credit: Justin Simoni
With a weight-to-volume ratio of 0.53 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 high-performance (but more expensive) EPX70 RS fabric, which is svelte and boasts excellent tear strength. The Granite Crown3 has the same 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 the 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. That has changed recently for the better, with pack makers coming up with innovative ways to make their packs more adjustable, providing more comfort and utility 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. The Granite Gear Virga3 includes the same style hip belt, as well as width-adjustable shoulder straps and an extremely adjustable torso length.
The shoulder straps of Nashville Pack's The Cutaway are removable, which allows you to swap different lengths. They attach to the top of the pack by a trio of burly straps, which also allows you to adjust shoulder width.
Credit: Justin Simoni
Nashville Pack offers an impressive list of options to customize The Cutaway before it even gets shipped to you. You're able to pick the torso length of the pack, and you have the option to pick out the right shoulder strap length to better accommodate different body shapes. (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 – or even switch them out for different shoulder straps!
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 them 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).
The ability to remove the hip belt, back padding, and metal frame gives you the option to start with a much lighter pack.
Packs like the Mariposa allow you to trim down on the weight you're carrying by removing parts.
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.
The hip belt, back stay and the two side cinch straps can be removed from the Hyperlite Mountain Gear Unbound 40 if you would like to save several ounces when hiking in with a lighter carry.
Many components of the Black Diamond Beta Light 45 can be stripped off for further gram savings, making this an extremely modular pack. The most weight savings come from removing the hip belt.
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.
