Guide 3 min
Is a 40-litre backpack enough for a wild camp?
40 litres is the floor of the wild-camp range. One summer night, solo, it holds; winter or with others, it doesn't. The maths, and the three thresholds.
You've got a 40-litre backpack, or you're hesitating over buying one, and you want to know whether you can head out and sleep under the stars with it. The honest answer isn't "yes" or "no": it's "it depends on what you put in it", and that can be worked out.
40 litres is the floor of the wild-camp range (40 to 50 L). For one summer night, solo, it holds with room to spare. In winter, with others, or over three nights, it gives way. Here's where the tipping point sits.
What actually fills the bag
The volume doesn't come from how long you're out, it comes from three items: the sleeping bag, the sleeping mat and the tent. The full method, with the litres-per-kilo coefficients, is in the guide What backpack volume. Here, we apply it to the specific case of 40 litres.
Here's a typical summer kit, for one night, solo:
| Item | Weight | Packed volume |
|---|---|---|
| Summer sleeping bag | 0.9 kg | 7 L |
| Sleeping mat | 0.5 kg | 3 L |
| 1-person tent | 1.3 kg | 6 L |
| Stove, gas, cookpot | 0.7 kg | 2 L |
| Down jacket | 0.4 kg | 2 L |
| Fleece and rain jacket | 0.6 kg | 2.5 L |
| Food (2 days) and water | 1.9 kg | 5 L |
| Everything else (head torch, first aid, hygiene) | 1 kg | 3 L |
That comes to around 30 litres. A 40 L backpack swallows it without straining, and there's room left to tighten the straps rather than cram. On that trip, 40 litres isn't tight: it's comfortable.
When is a 40 L bag not enough?
A 40 L bag gives way in winter, over three nights or more, and with two people or more.
Winter. The sleeping bag is the bulkiest item: each kilo costs 8 litres. A sleeping bag that goes from 0.9 to 1.6 kg means 13 litres instead of 7, six litres more on its own. The sleeping mat gains insulation, the down jacket gains warmth. You go past 45 litres without even noticing.
Three nights or more. Food stacks on top of everything else, at 0.7 kg per day per person. Three days already makes more than 2 kg of food, and it's the line gear lists forget to count towards the volume. At that point you're not wild camping any more but trekking, range 50 to 65 L.
Two people or more. The tent grows, and the shared gear adds to yours. With four people on a wild camp, the gear goes past 70 litres: no backpack in the 40-50 range can work any more, even splitting the load.
Check your case in thirty seconds
Weigh your sleeping bag, your sleeping mat and your tent. Multiply by 8, 6 and 4.5. Add them up, then add two or three litres of food per day. If you stay under 30 litres, a 40 holds; if you're getting close to 40, take a 45 or 50: a bag that won't close ends up with the sleeping mat strapped to the outside, in the rain.
Related guides
- What backpack volume for a day hike, a wild camp, a trek?
- What backpack volume when you hike as a group?
What to remember
- Summer, one night, solo: 40 litres is enough, with room to spare.
- Winter, three nights, or with others: move up to 45-50, or beyond.
- The sleeping bag decides. A compressible bag gains you more than a lighter stove.
Your own kit isn't the typical kit: your sleeping bag, your tent and the weather on your trip change the total. Describe your trip, and compare the estimated volume with the capacity we suggest, right next to it.
Written by Thanaël Fontaine. Published .