Backpacking Food Weight Calculator

What this calculator does

Food is the one part of your pack weight that changes every trip. Your tent and stove weigh the same every time. Your food bag depends on how many days you're out, how hungry you get and what you choose to carry. This calculator turns those three inputs into one number: the grams of food that go in the pack.

The math is simple, and that's the point. Multiply days by calories per day to get the trip's total energy. Then divide by the average calorie density of your food, in kilocalories per 100 grams, and multiply by 100. The result is the food weight in grams. The tool also gives it in kilograms and pounds, plus a per-day figure you can use to split your food into daily bags.

Choosing your inputs

Trip length

Count the meals you will actually eat on the trail, not the number of nights. For a typical overnight you might eat lunch, snacks and dinner on day one, then breakfast, snacks and lunch on day two. That's closer to 1.25 days of food than to 2. Entering a decimal is fine and gives a more honest answer than rounding up "just in case". Pack a deliberate emergency reserve instead (see below).

Calories per day

This is the input with the most uncertainty. Energy use on the trail depends on body size, pack weight, terrain, temperature and pace. Our hiking calorie estimator gives a rough figure for the walking part of the day. Add your normal resting needs on top. Many backpackers plan somewhere between 2,500 and 4,000 kcal a day. They also accept that on longer trips they'll run a deficit, because carrying enough food to match a hard day's burn gets heavy fast.

If you're unsure, think about how much you eat on a busy day at home and add a margin. Then check after the trip: did you come home with leftovers or run out? That record is worth more than any formula.

Average calorie density

Density is what turns a heavy food bag into a light one. A food bag that averages 125 kcal per ounce (about 440 kcal per 100 g) weighs a third less than one that averages 85 kcal per ounce (about 300 kcal per 100 g) for the same energy. You can find any food's density from its nutrition label with the calorie density checker.

To get the average for your bag, add up the calories of everything you plan to bring and divide by the total weight. Or start with a rough guess. Mixed bags with plenty of nuts and nut butter often land around 450 kcal per 100 g. Bags built on dehydrated dinners, oatmeal and bars tend to sit lower, around 380 to 420.

Worked example

Say Lena is planning a three-day, two-night trip. She'll start after breakfast on day one and finish mid-afternoon on day three, so she plans 2.5 days of food. She expects to need about 3,000 kcal a day. Her food list averages 450 kcal per 100 g.

If Lena swapped half her nut butter for fresh apples and her density fell to 350 kcal per 100 g, the same 7,500 kcal would weigh 2,143 g. That's almost half a kilogram more for the same energy. This is why so much backpacking food advice comes back to fats and dry foods.

Quick reference tables

Total food weight at 3,000 kcal a day

Food per day by calorie target

Read across a row to see what better density saves. At 3,000 kcal a day for a week, moving from 350 to 450 kcal per 100 g saves about 1.3 kg.

How to use the calculator, step by step

1. Count food days, using the meal-based method above. Decimals are fine.
2. Pick a daily calorie target. Start from your own experience or the hiking calorie estimator.
3. Estimate your average density. Use 400 to 450 kcal per 100 g as a starting guess if you haven't built a list yet.
4. Read the total and per-day weight.
5. Build your real food list, add up its calories and grams, and run the calculator again with the true density.
6. Add your emergency reserve as a separate, known weight.

Planning resupplies

On long routes, you'll carry food only to the next resupply point. Run the calculator once per section. The longest section usually sets your heaviest pack. For example, at 3,500 kcal a day and 450 kcal per 100 g:

The five-day section is the crux. If that weight is too much, look for a resupply in the middle, a denser food plan or a slightly lower daily target for that stretch only.

Packaging weight

The calculator counts food, not packaging. Original packaging can add a surprising amount: boxes, trays and thick wrappers. Repackaging at home into zip bags usually saves weight and space. Keep the nutrition labels (or a photo of them) so you still know what you're carrying. Write the calories and day number on each bag with a marker, so it's easy to check on the trail that you're eating to plan and not running short. Pack each day's bag in the order you'll need it, with day one on top. If you leave food in its packaging, weigh a few items to see what the packaging adds.

Sample food list for one day

This made-up list shows how a 3,000 kcal day can come together at about 450 kcal per 100 g:

That's about 441 kcal per 100 g, a good, realistic average. Your own numbers will differ by brand.

Glossary

• Food day: a full day's worth of trail meals and snacks.
• Average density: total calories divided by total grams, times 100.
• Base weight: pack weight without food, water and fuel (not used by this calculator).
• Resupply: a place where you buy or collect food partway through a route.

Adjusting the inputs by trip type

These are planning ranges used by many hikers, not personal recommendations. Your own trip records are the best guide.

Food weight in context

Food is usually the second-heaviest consumable after water, and on long stretches without resupply it can outweigh everything else. A week of food at 3,000 kcal a day and 450 kcal per 100 g is about 4.7 kg, which for many lightweight hikers is comparable to the shelter, sleeping bag and pack combined. That's why a few minutes with this calculator often saves more weight than an expensive gear upgrade.

Food weight also falls every day of the trip. Your pack will be at its heaviest on the first morning and lightest on the last afternoon. If the first day includes the biggest climb, consider eating the heaviest foods first, or rearranging the route so the hardest day comes later.

Checking your plan after the trip

When you get home, weigh any food left over and note it alongside the trip length, weather and how hungry you felt. After two or three trips you'll know whether to raise or lower your daily target, which makes the next run of the calculator much more accurate. Note which foods came home uneaten, too. They're usually the foods to swap first, because carrying food you don't want to eat is the least efficient weight in your pack. A short note on your phone after each trip, with days, kcal planned, density and leftovers, is enough.

Adding a safety reserve

Don't pad every day's calories. Pack one extra block of dense food, such as a bar or two and a bag of nuts, as your emergency reserve. That keeps your planning honest, and you know exactly what the reserve weighs. On remote routes, or when weather could keep you out longer, plan a whole extra day. Run that extra day through the calculator so you can see its cost in grams.

Common mistakes

• Planning by meals instead of calories. Five dehydrated dinners might sound like plenty, but at 600 kcal each they cover only a fraction of a long day.
• Forgetting drinks. Electrolyte mixes, hot chocolate and powdered milk add calories and weight. Include them.
• Ignoring appetite changes. Many people aren't hungry on day one, then get very hungry by day four or five. On long trips, shift a little more food into the later days.
• Counting water-heavy foods at their label density. Tortillas, cheese and salami are good trail foods, but they have more water than nuts. Check their real density.

How this fits with the other tools

Once you know your total grams, use the multi-day trail meal planner to split each day into breakfast, lunch, snacks and dinner. The trail mix builder helps you design a dense snack mix. For a full walkthrough, read our guide to planning a 3-day backpacking meal plan.

Limits of the estimate

This is a planning tool, not a nutrition prescription. It does exactly the arithmetic described above and nothing more. It doesn't know your metabolism, the weather or the trail. If you have a medical condition that affects what you eat, plan with a qualified professional. The tool still works well for the logistics.