Water Intake Calculator
Estimate daily water with a simple weight-and-exercise formula, shown in liters, milliliters, US cups and fluid ounces.
About the Water Intake Calculator
This water intake calculator applies a simple rule of thumb: 33 milliliters per kilogram of body weight, plus 355 milliliters for each 30 minutes of exercise. For 70 kg with no exercise, the formula returns 2.31 liters. Choose kilograms or pounds, enter your inputs, and compare the estimate in liters, milliliters, US cups and fluid ounces. This arithmetic does not determine an individual medical hydration requirement or account for health conditions, climate or differences in sweat loss.
Features
- Weight input in kilograms or pounds
- Explicit 33 ml/kg formula plus exercise adjustment
- Results in liters, milliliters, US cups and fluid ounces
- Copy or download the estimate
How to use this tool
The Water Intake Calculator works right in your browser — no signup, no installation. Follow these steps:
- Choose kilograms or pounds.
- Enter weight and exercise minutes.
- Read the formula estimate and its stated limits.
- Copy or download the result if useful.
Frequently asked questions
What formula does the calculator use?
Weight in kilograms × 33 ml, plus exercise minutes ÷ 30 × 355 ml. The cups display uses a US cup of approximately 236.588 ml.
Is this my medically recommended water intake?
No. It is a general arithmetic estimate from two inputs, not an individualized recommendation. If you have a prescribed fluid target, use that guidance instead.
Using the results
Use the Water Intake Calculator to calculate from the values you enter. Check the displayed units, rounding and supported inputs when interpreting the result.