Water Intake Calculator
Work out how much water to drink per day from your weight, activity and the climate you live in.
Inputs
Formula
- Base = 35 ml × weight (kg)
- Add 350 ml per 30 min of exercise
- Hot climate adds 10–15%
Roughly 35 ml of fluid per kilogram of body weight covers a normal day, before exercise and heat. Food supplies about 20% of it, so the glasses figure below is deliberately conservative — thirst and pale urine remain the best day-to-day check.
Step-by-step calculation
- 1
Base
35 ml × kg
2,450 ml
- 2
Total
(base + exercise) × climate
2,800 ml
Frequently asked questions
What does the Water Intake Calculator do?
Work out how much water to drink per day from your weight, activity and the climate you live in. The Water Intake Calculator on OneCalcApp returns the result instantly as you type, together with the formula and the substituted values.
How do I use the Water Intake Calculator?
Enter your values in the input fields, choose the relevant units or options, and the Water Intake Calculator recalculates automatically. You can copy, print or export the result.
Is the Water Intake Calculator free to use?
Yes. The Water Intake Calculator is completely free, needs no sign-up and has no usage limit on OneCalcApp.
How accurate is the Water Intake Calculator?
It uses the standard formula Base = 35 ml × weight (kg) and full double-precision arithmetic, so results match a manual calculation to the displayed number of digits.
Does the Water Intake Calculator work on mobile and offline?
Yes. The Water Intake Calculator runs entirely in your browser on phones, tablets and desktops, and your inputs never leave your device.
Where can I find related tools?
OneCalcApp hosts 300+ calculators and converters, including the full Health collection. Related tools are linked at the bottom of every page.
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