Water Intake Calculator
Estimate how much water you may need each day based on your body weight, activity level, and exercise duration.
Calculate your daily water intake
Enter your weight and activity information to get an estimated daily water intake recommendation.
Your result
—
| Weight | — |
| Activity level | — |
| Exercise duration | — |
| Base water estimate | — |
| Exercise adjustment | — |
| Estimated daily water intake | — |
Step-by-step calculation
What does the result mean?
The result is an estimate of the amount of water you may need to drink each day based on your body weight and physical activity.
Your actual fluid needs can vary depending on climate, temperature, sweating, diet, health, medications, and the intensity and duration of physical activity.
Water from foods and other beverages can also contribute to your overall daily fluid intake.
How is water intake calculated?
This calculator starts with a simple body-weight-based estimate of daily water needs and then adds an adjustment for exercise.
For this calculator, the base estimate is 35 millilitres of water per kilogram of body weight. Exercise adds an additional estimated amount based on activity duration.
Water intake example
Suppose a person weighs 70 kg and exercises for 30 minutes per day.
Base water estimate = 2,450 ml
Exercise adjustment = 30 × 12
Exercise adjustment = 360 ml
Total = 2,450 + 360
Total = 2,810 ml/day
The estimated daily water intake is approximately 2.81 litres.
Formula used
Exercise adjustment = exercise minutes × activity factor
Daily water intake = base water intake + exercise adjustment
The calculator provides an estimate rather than a medically prescribed fluid requirement.
Related calculators
Important: This calculator provides a general estimate for informational purposes only. Individual fluid needs can vary significantly based on health, environment, diet, medications, sweating, and physical activity. This tool is not medical advice and should not replace guidance from a qualified healthcare professional.