For hiking pack capacity, my picks are 21L for day hikes, 30L for hut stays and 50L for tent camping: the Deuter Speed Lite 21 for day hikes, the Mammut Lithium 30 for huts and the Millet Saas-Fee NX 50+ for tent camping. If you're buying your first pack, I'd take the 30L Lithium 30.
The Gear Nerd's Pick
The bigger the pack, the heavier it gets per liter. Lined up, my four picks are 20.6g at 12L, 22.4g at 21L, 31.0g at 30L and 35.0g at 50L. Buy one 50L pack and use it for day hikes too, and you carry over 1kg of extra empty pack, so I size the pack to the load for the trip I'm doing.
Key points
- The four picks weigh 247g to 1,750g. Divided by capacity that's 20.6–35.0g per liter, and the bigger the pack, the heavier it is
- Among day packs around 20L, the 470g Speed Lite 21 and the 740g Lithium 20 are 270g apart. The Lithium 20 is the one listed with a rain cover
- Osprey gives a range for the weight you carry, separate from capacity. It's 5–14kg for the Stratos 34 and 11–16kg for the Atmos AG 50
Choose hiking pack capacity by use: day hike 21L, hut stay 30L, tent camping 50L
Choose pack capacity by the trip you're taking. My picks are 21L for day hikes, 30L for hut stays, 50L for tent camping and 12L for running trips.
A 50L pack is heavy even empty. Millet lists the Saas-Fee NX 50+ at 1,750g, and the Deuter Speed Lite 21 at 470g. That's a 1,280g gap, about two and a half 500mL bottles of water.
If you buy one 50L pack on the "bigger covers everything" logic, you carry that weight on every day hike too. So I split use into four and picked one pack for each.
How I chose
Here's the order I looked at things when choosing capacity.
- The trip. I split it into four: day hike, hut stay, tent camping and running.
- Weight per liter, which is weight divided by capacity. I compare packs of the same use against each other, and the lighter one becomes a candidate for my pick.
- Whether it comes with a rain cover, and whether the official page gives a back length.
What I couldn't decide was the day-hike pick: the Speed Lite 21, 270g lighter, or the Lithium 20 with a cover included.
Pack capacity by use, and the four picks
Scroll the table sideways →
| Use | My pick | Weight and capacity | Official price | Weight per liter |
|---|---|---|---|---|
| Day hike | Deuter Speed Lite 21 | 470g · 21L | ¥14,850 | 22.4g |
| Hut stay | Mammut Lithium 30 | 930g · 30L | ¥23,100 | 31.0g |
| Tent camping | Millet Saas-Fee NX 50+ | 1,750g · 50L | ¥39,600 | 35.0g |
| Running / fast hiking | Salomon ADV Skin 12 | 247g · 12L | ¥19,800 | 20.6g |
From 12L to 50L, weight per liter climbs from 20.6g to 35.0g. The bigger the pack, the heavier it is for its capacity. That's why I split by use.
How many liters for a day hike? My pick is the 21L Deuter Speed Lite 21
470g for 21L. At 22.4g per liter, it's about as light as a running vest. This is where I recommend it with some heat. It's 270g lighter than the Mammut Lithium 20, a similar 20L pack, and ¥3,850 cheaper.
Here's the weak spot. The product page mentions neither a rain cover nor a back length. On rainy days you'd put your gear in waterproof bags, so it suits day hikes with a light load.
Image: Rakuten Ichiba
Deuter Speed Lite 21
Lowest price on Rakuten: ¥10,694 (as of 10/14). Prices vary by shop, up to ¥15,750, and change daily.
RecommendedSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanIf you want a cover from the start, the Lithium 20 is for you. The official page lists an integrated rain cover, and it's 740g and ¥18,700. You'd be paying 270g for the cover and the back construction.
Image: Rakuten Ichiba
Mammut Lithium 20
Lowest price on Rakuten: ¥13,800 (as of 10/14). Prices vary by shop, up to ¥15,895, and change daily.
RecommendedSee it at L-BreathSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanCapacity for hut stays is 30L: Mammut Lithium 30
930g and ¥23,100, 31.0g per liter. A removable rain cover comes with it. Among the 6 models around 30L that I lined up, it also had the lowest weight and the lowest price.
Watch the missing back length on the 30L page. If your back is short or long, fit it in a shop before you decide. I put the ranking of the 6 models and a back-length table in 30L pack rankings.
Image: Rakuten Ichiba
Mammut Lithium 30
Lowest price on Rakuten: ¥16,800 (as of 10/13). Prices vary by shop, up to ¥29,900, and change daily.
RecommendedSee it at L-BreathSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanCapacity for tent camping is 50L: Millet Saas-Fee NX 50+
1,750g for 50L, 35.0g per liter. The maker bills it as ideal for tent-camping traverses carrying a lot of heavy gear, and it comes with a rain cover that fits two compartments. It's 210g lighter than the Osprey Atmos AG 50 I compared and ¥14,300 cheaper.
Watch the back length: only M at 48cm and L at 51cm. For a back shorter than 48cm there's no size that fits on paper. It suits someone with a 48–51cm back looking for a first tent-camping pack.
Image: Rakuten Ichiba
Millet Saas-Fee NX 50+
Lowest price on Rakuten: ¥33,819 (as of 10/14). Prices vary by shop, up to ¥39,600, and change daily.
RecommendedSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanIf your back is short, go for the S/M of the Atmos AG 50. The back length adjusts between 40.5 and 51cm, and a 3D back-panel mesh lets air through. In exchange it's 1.96kg and ¥53,900, so both weight and price go up.
If you'll carry even heavier loads, I judged the 2026 model in the Gregory Baltoro 65 review.
For running or fast hiking, 12L: Salomon ADV Skin 12
247g for 12L. It's shaped like a vest you wear more than a pack you carry. It comes in five sizes from XS to XL, and it's built for long trail runs of 60km or more.
Here's the weak spot. At 12L, a hut stay's gear won't fit. It has no rain cover and can't stand in for a pack on a walking trip. It's only for people who run trails, and people who trim their load and move fast.
Image: Rakuten Ichiba
Salomon ADV Skin 12
Lowest price on Rakuten: ¥19,800 (as of 10/14). Prices change daily.
RecommendedSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanIf you're after fast day hikes, there's also the karrimor AR 20 review.
The packs I compared against my picks
Scroll the table sideways →
| Model | Weight and capacity | Official price | Weight per liter | Difference from my pick |
|---|---|---|---|---|
| Mammut Lithium 20 | 740g · 20L | ¥18,700 | 37.0g | +270g · +¥3,850 |
| Osprey Atmos AG 50 (S/M) | 1.96kg · 50L | ¥53,900 | 39.2g | +210g · +¥14,300 |
Packs have a carrying-weight range, separate from capacity
Osprey gives each pack a "recommended packing weight." It's 5–14kg for the 34L Stratos 34 and 11–16kg for the 50L Atmos AG 50. The capacity differs by 16L, but the upper numbers differ by only 2kg.
The big difference is in the lower numbers, 5kg and 11kg. On paper, a trip where your load doesn't reach 11kg falls outside what the Atmos AG 50 is designed for. I read a big pack as less a thing that holds a lot and more a thing for carrying heavy loads.
Who is it for?
This way of choosing suits people who've already decided what trips they take. If it's only day hikes, 21L; once you start thinking about huts, 30L. You can match your first pack to the trip. If you pick Millet at 30L, the Saas-Fee NX 30+5 review goes as far as the difference from the 40+5.
If you do mostly day hikes, you can also keep a separate 20–30L pack alongside the 50L. If you carry poles on the outside, check the stowed length too so they don't get in the way at the side of the pack. I compared lengths and stowed lengths in trekking pole rankings.
If you already own one pack around 30L and only do day hikes and one-night hut stays, that one is enough. You can wait on a 50L until after you've bought a tent and sleeping bag, and the vest shape is for people who run in the mountains, so if you only walk there are other ways to choose.
FAQ
How many liters should my first hiking pack be?
I'd choose 30L. The Lithium 30 is billed as a 30L pack for both light hikes and tough tours, and it's big enough to cover day hikes and a one-night hut stay with a single pack.
Is 30L too big for day hikes?
I don't think it's too big. The Lithium 30 weighs 930g, a 460g gap to the 21L Speed Lite 21 (930 − 470). If you've decided on day hikes only, the 21L keeps things lighter.
Can I use a 50L pack for day hikes?
You can, but the Saas-Fee NX 50+ is 1,750g empty, 1,280g heavier than the Speed Lite 21. If you hike mostly day trips, keeping a separate 20–30L pack lets you walk lighter.
What do I do in the rain if the pack has no rain cover?
Add a separately sold cover, or put your gear in waterproof bags. A cover only wraps the outside and leaves the back side open, so keep your spare clothes in a bag either way.
Gear in this article
Ad · Images: Rakuten IchibaSources
- Iwatani-Primus (Deuter's authorized distributor in Japan) official page: Speed Lite 21
- Mammut official online store: Lithium 20 (2530-03172)
- Mammut official online store: Lithium 30 (2530-03152)
- Millet official online store: Saas-Fee NX 50+
- Blue Sheep (Osprey's authorized distributor in Japan) official store: Atmos AG 50
- Blue Sheep (Osprey's authorized distributor in Japan) official store: Stratos 34
- Salomon official online store: ADV Skin 12
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