Outdoor Calculators
Camping water.
Set the group, the days, the activity and the heat and get a conservative daily and total water figure for drinking, cooking and washing up. Starts from the U.S. National Academies drink intake. Runs in your browser; nothing is sent or stored.
Trip
Result
Fill the form and press Calculate.
Worked example
Four people, 3 days, mixed group, light hiking in mild weather. Drinking: 2.6 + 0.5 + 0.25 = 3.35 L per person per day. Add 0.5 L for cooking and washing = 3.85 L. For the group: 3.85 x 4 x 3 = 46.2 L (12.2 US gal), which weighs 46 kg.
How it works
Water per person per day = drinking baseline + activity allowance + heat allowance + cooking and washing. The baseline is the drink portion of the adequate intake set by the U.S. National Academies: about 3.0 L for men and 2.2 L for women (total water including food is 3.7 and 2.7 L). Mixed groups use the 2.6 L average.
The activity (0 to 1.5 L) and heat (0 to 1 L) allowances are conservative planning figures, not clinical values: sweat loss varies a great deal between people. Water weighs 1 kg per litre, so on foot carry what you need to the next reliable source and treat water from streams and lakes. Not medical advice; people with medical conditions should follow their clinician.
Sources and basis: Institute of Medicine / National Academies, Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (2004): adequate intake of total water 3.7 L (men) and 2.7 L (women) per day, about 3.0 L and 2.2 L from beverages. Activity, heat and cooking allowances are planning figures. Checked 2026-10-05. Planning guide only, not medical or safety advice. Conditions, health and equipment change real needs; use your own judgment and local guidance.
FAQ
How much water do I need per person per day camping?
Plan at least 3 to 4 litres (about 1 gallon) per person per day for drinking and cooking in mild weather, and more in heat or with hard effort.
How many gallons of water per person per day?
About one US gallon (3.8 L) per person per day is the common planning figure for camping. This calculator shows litres and gallons for your conditions.
Does the 3.7 L figure mean I should drink that much?
No. It is total water including about 20% from food. The drink portion is about 3.0 L for men and 2.2 L for women, for healthy adults at moderate temperatures.
How do I carry less water?
Plan around reliable sources and carry a filter, purifier or tablets. Treat all backcountry water before drinking.
Is this medical advice?
No. It is a planning aid. Heat illness and dehydration are serious; know the symptoms and turn back if anyone in the group has them.