Use our free Water Intake Calculator to get a clear estimate in seconds. Enter your values and see an instant result. Create a free account if you want your inputs saved for next time.
How to use this water intake calculator
- Enter each requested value using the units displayed beside the field.
- Select any options that match your situation, then choose Calculate result.
- Review the main answer and supporting values. Change any input to compare another scenario.
The formula
Base water = 35 ml per kilogram of body weight, plus 350 ml per 30 minutes of exercise.
The calculator uses the full precision of your inputs and rounds only the values shown on screen. This helps avoid compounding rounding errors.
Worked example
A 70 kg person exercising for 30 minutes gets an estimated target of 2.8 liters per day.
Keep in mind: This result is an estimate for planning and education. It does not replace personalized financial, medical, legal, or other professional advice.