A 35 to 40 liter pack is the size most hikers grow into. It handles all-day hikes with layers, food and water, and it is just big enough for a summer overnight with compact gear.
Our picks range from Osprey’s adjustable Kestrel LT 35 and Kyte 38 to budget packs with frames, bladders and rain covers.
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Quick Picks
- Best overall: Osprey Kestrel LT 35
- Best for women: Osprey Kyte 38 Women’s
- Best value framed: Naturehike Rock 40+5L
- Best budget: Maelstrom 40L Waterproof Backpack
- Best with bladder: IX INOXTO 40L with 3L Bladder
- Best packable: MIYCOO Ultralight Packable 35L
Comparison Table
| Product | Best for | Capacity | Standout feature | |
|---|---|---|---|---|
| Osprey Kestrel LT 35 | Best overall | 35L | Adjustable torso, raincover | View |
| Osprey Kyte 38 Women’s | Best for women | 38L | AirScape back, adjustable torso | View |
| Naturehike Rock 40+5L | Best value framed | 40+5L | Internal frame, hydration-ready | View |
| Maelstrom 40L Waterproof Backpack | Best budget | 40L | 9 pockets, water-resistant fabric | View |
| IX INOXTO 40L with 3L Bladder | Best with bladder | 26L/40L | Includes 3L water bladder | View |
| MIYCOO Ultralight Packable 35L | Best packable | 35L | Folds to 4.5 x 3.9 x 7.8 in | View |
Detailed Reviews
1The Kestrel LT 35 is a classic top-loading rucksack with a men’s fit and an adjustable torso length, so you can dial it to your back instead of hoping a fixed size works.
Osprey gives it a fixed top lid with a zip pocket, stretch side pockets, a front shove-it pocket, trekking pole attachments and a side zip that reaches into the main compartment without unloading from the top. It ships with a raincover. At 35 liters it is the right size for long day hikes and efficient overnights where you carry a light sleep system.
Pros & Cons
What we like
- Adjustable torso length
- Side-zip access to main compartment
- Raincover included
Watch out for
- Men’s fit only in this listing
- 35L is tight for cold-weather overnights
Key Specs
- Capacity: 35 liters
- Fit: men’s, adjustable torso
- Loading: top lid plus side zip
- Raincover: included
- Extras: trekking pole attachment, shove-it pocket
2The Kyte 38 is Osprey’s women’s hiking pack in the 40L class. Its injection-molded AirScape back panel lets you adjust torso length and keeps the load close and stable on technical ground.
It comes with an integrated raincover, trekking pole attachment, a top lid and a fixed hip belt. It is a strong pick for long day hikes, hut-to-hut routes and light overnights for women who want a dialed fit.
Pros & Cons
What we like
- Women’s fit with adjustable torso
- Raincover included
- Stable carry on rough trails
Watch out for
- Fixed hip belt
- Premium pricing
Key Specs
- Capacity: 38 liters
- Fit: women’s, adjustable torso
- Back panel: AirScape
- Raincover: integrated
- Extras: trekking pole attachment
3Naturehike’s Rock pack combines a 40-liter body with a 5-liter extension, an internal frame, a rain cover and a hydration port. The brand lists it at 22 x 10.2 x 7.1 inches.
Ergonomic shoulder straps and a padded back panel make it a real trekking pack rather than a stretched daypack. Naturehike is a well-known camping brand, and this pack sits between budget no-names and premium Osprey models.
Pros & Cons
What we like
- Internal frame
- 40L plus 5L extension
- Rain cover and hydration port
Watch out for
- Fit range not as adjustable as premium packs
- Fewer reviews than Osprey
Key Specs
- Capacity: 40 + 5 liters
- Size: 22 x 10.2 x 7.1 in (brand listing)
- Frame: internal
- Rain cover: included
- Hydration: compatible
4This version of the Maelstrom swaps to a more water-resistant fabric and spreads storage across nine pockets: the main compartment, two front zip pockets, two hip-belt pockets, two side pockets and two mesh pockets.
The brand lists the pack at about 13.4 x 8.6 x 22 inches, a tall and narrow shape that stays close to your back on narrow trails and in crowded train aisles. Hip-belt pockets are the standout here; snacks, a phone and a map stay reachable without stopping. Like the standard Maelstrom it has no real frame, so treat it as a big daypack rather than an overnight hauler.
Pros & Cons
What we like
- Two hip-belt pockets for snacks and phone
- Water-resistant fabric
- Slim profile for trails and transit
Watch out for
- No frame for heavy loads
- Back panel runs warm in summer
Key Specs
- Capacity: 40 liters
- Size: about 13.4 x 8.6 x 22 in (brand listing)
- Pockets: 9 including 2 hip-belt pockets
- Fabric: water-resistant nylon
- Frame: none
5IX INOXTO bundles a 3-liter water bladder and a rain cover with its hiking pack, which is unusual at this price. It is offered in 26L and 40L sizes; choose the 40L.
The fabric is high-density water-resistant polyester, and stress points and straps are reinforced. Hands-free hydration is the selling point: you drink more often when you do not have to stop and dig out a bottle.
Pros & Cons
What we like
- 3L bladder included
- Rain cover included
- Reinforced stress points
Watch out for
- Bladder quality is basic
- No frame
Key Specs
- Capacity: 40 liters (also 26L)
- Hydration: 3L bladder included
- Fabric: water-resistant polyester
- Rain cover: included
6MIYCOO’s packable daypack folds down to about 4.5 x 3.9 x 7.8 inches and, according to the brand, weighs about half as much as a phone. Unfolded, it is 12.5 x 8.5 x 20.9 inches.
The fabric has an IPX4 splash rating, so light rain is fine but a downpour is not. It is the lightest way to carry 35 liters, but there is no padding, so keep loads small.
Pros & Cons
What we like
- Folds very small
- IPX4 splash resistance
- Extremely light
Watch out for
- No padding or frame
- Not for heavy gear
Key Specs
- Capacity: 35 liters
- Folded: 4.5 x 3.9 x 7.8 in
- Unfolded: 12.5 x 8.5 x 20.9 in
- Water resistance: IPX4 (brand)
How We Chose
We compared published specs, materials, fit ranges and features for more than 40 backpacks in the 30 to 50 liter range, then read verified owner feedback to spot durability and comfort problems that spec sheets miss. We did not receive free products, and we do not claim hands-on testing. TOR Scores combine published specs, verified owner feedback and overall value.
What to Look for in a 40L Hiking Backpack
Forty liters is the sweet spot between a daypack and a full backpacking pack. It holds the Ten Essentials, layers for changing weather, lunch, three liters of water and still has room left for a light sleeping bag on an overnight. Here is what separates a good hiking pack from a big school bag.
- Frame or no frame. Frameless packs (Maelstrom, Nerlion) are light and cheap but feel heavy above about 20 pounds. Internal frames (Osprey, Naturehike, N NEVO) move weight onto your hips and stay comfortable to 30 pounds or more.
- Hip belt. A padded hip belt carries most of the load. A thin webbing strap only keeps the pack from swinging.
- Back ventilation. Mesh or channeled back panels reduce the sweaty patch on hot climbs.
- Rain protection. Most packs are water resistant, not waterproof. A rain cover or a liner bag keeps your sleeping bag and spare clothes dry.
- Hydration. A bladder sleeve and hose port let you drink without stopping, which helps you drink enough.
- Access. Side zips, front shove-it pockets and hip-belt pockets save you from unpacking the whole bag for one item.
For long day hikes, a frameless pack is fine. If you plan to carry a tent, stove and sleeping bag, choose a framed pack with a padded hip belt.
What Fits in a 40L Pack
A 40-liter pack is enough for a fast overnight in summer, a hut trip, or a week of travel if you pack light. A typical summer overnight load looks like this:
- Ultralight one-person tent or hammock (2 to 4 liters packed)
- Compressible sleeping bag rated for the season (5 to 8 liters)
- Inflatable sleeping pad (1 to 2 liters)
- Stove, fuel and small pot (2 liters)
- Food for one to two days (3 to 5 liters)
- Rain jacket, warm layer and spare socks (5 liters)
- Water: 2 to 3 liters in bottles or a bladder
- Ten Essentials: navigation, headlamp, sun protection, first aid, knife, fire, emergency shelter
If your sleeping bag is bulky synthetic, or you hike in shoulder season with heavier layers, step up to a pack with an extension collar or roll-top, like the Naturehike Rock 40+5 or Haimont 40+15. For travel, 40 liters holds about five to seven days of clothes with packing cubes.
Related guides: best 30 40L hiking backpack, best 40L backpack for hiking, best 40L backpack hiking, best 40L backpack for women. Browse every pick in our backpacks category.
Sources and further reading: National Park Service: the Ten Essentials, Leave No Trace: the 7 Principles and National Park Service: camping basics. Product specs come from brand listings on Amazon; always check your airline’s current carry-on size rules before you fly.
Frequently Asked Questions
Is a 40L backpack big enough for an overnight trip?
Yes, for a summer overnight with compact gear. A light tent, a compressible sleeping bag, a small stove and one or two days of food fit in 40 liters. Cold-weather trips with bulky layers usually need 50 liters or a pack with an extension collar.
Do I need a frame in a 40L backpack?
If you will carry more than about 20 pounds, yes. An internal frame and padded hip belt move weight onto your hips. For lighter day hikes and travel, a frameless pack is fine.
Are 40L backpacks waterproof?
Most are water resistant rather than waterproof. Seams and zippers let water in during heavy rain. Use a rain cover or a liner bag for anything that must stay dry.
How much should a 40L pack weigh empty?
Frameless 40L packs often weigh around 1 to 2 pounds, while framed hiking and travel packs usually weigh 2.5 to 4 pounds. Wheeled backpacks are heavier, often 4 to 6.5 pounds.
How do I clean a backpack?
Empty it, shake out debris, and hand wash with mild soap and lukewarm water. Avoid the washing machine unless the brand allows it, and air dry away from direct heat.
Final Verdict
For a 35-40L hiking backpack, the Osprey Kestrel LT 35 is our first choice, while the Osprey Kyte 38 is the women’s pick. The Naturehike Rock 40+5 offers an internal frame for less.
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