What this calculator does#
It estimates daily calorie needs from body weight, effort, pack load and temperature, then converts the total into the mass and volume of food that lands in your pack, at the calorie density your menu actually achieves.
How the maths works#
Baseline is per kilogram of body weight, because a 55 kg and a 95 kg hiker on the same trail differ by roughly a third: 33 kcal per kg for basecamp days, 45 for moderate hiking, 58 for hard days, 70 for very long days or winter travel.
Load adds about 15 kcal per kilogram of pack weight per day.
Cold adds 10 percent, covering both the metabolic cost and the extra hot drinks.
Mass is total calories divided by calorie density in kcal per gram. This is the lever that matters: the same 3,000 kcal a day weighs 750 g at 4.0 kcal per gram and 600 g at 5.0.
Volume is estimated at 1.5 litres per kilogram, which suits a mixed menu with some freeze dried components.
Nobody eats to requirement#
On trips under about a week, most people run a deficit of 500 to 1,000 kcal a day without harm, because appetite lags effort and the body draws on reserves. That is why experienced hikers carry less than a calculator says and are fine.
Past about ten days the deficit stops being free. It shows up as a pace you cannot hold, poor recovery, and a sudden hunger that arrives with a resupply town. Plan short trips to the low end of the range and long trips to the full figure.
Frequently asked questions#
How much food per day for backpacking?#
Between 600 and 900 g per person per day for most three-season trips, with 700 g a reasonable planning figure. The spread is almost entirely calorie density, not appetite.
How many calories do I need hiking?#
Roughly 45 kcal per kilogram of body weight for a moderate day with a light pack, rising towards 70 for very long days, winter travel or a heavy load. For a 70 kg hiker that is about 3,150 kcal moderate and 4,900 hard.
What is a good calorie density for trail food?#
Aim for 4.5 kcal per gram across the whole food bag. Nuts, oils, nut butters, cheese and chocolate lift the average; fresh food, tinned food and anything packed in water pull it down hard.
Should I repack food out of its packaging?#
Yes on any trip longer than a night. Repacking a week of food routinely saves 200 to 400 g and a litre of volume, and it makes the food bag pack flat rather than in awkward boxes.
Do I need more food in winter?#
Yes, roughly 10 percent more, plus considerably more hot fluid. The bigger winter effect is on fuel rather than food, because melting snow costs about twice the energy of heating stream water.
How do I plan food for a group?#
Calculate per person, then check the group total against the pot volume and stove you are carrying. Groups usually over-cater breakfast and under-cater afternoon snacks, and the fix is to plan snacks by the day rather than as a shared bag.
Standards, sources and further reading
- Energy expenditure scales with body mass, which is why the model works per kilogram rather than from a flat daily figure.
- Load carriage adds energy cost roughly in proportion to the mass carried, modelled here at 15 kcal per kg of pack weight per day.
- This is a planning tool, not nutritional or medical advice.
How this page is made. Every number here is either a published standard, a physical constant, or arithmetic we show in full so you can check it. Read our evaluation method and editorial standards, or tell us we got something wrong.
Last reviewed and updated 9 September 2026.