Water Intake Calculator
Staying adequately hydrated supports performance, recovery, digestion and general health. This calculator gives a starting-point daily water target based on your body weight, with an add-on for exercise.
Fill in the form and select Calculate to see your result here.
What is Water Intake?
This calculator uses a commonly cited baseline of about 35 ml of water per kilogram of body weight, plus an additional allowance for fluid lost through exercise-related sweating.
Water Intake Formula
The baseline scales with body weight since larger bodies generally require more fluid for the same bodily functions. The exercise add-on accounts for extra fluid loss during physical activity, added in 30-minute increments.
Baseline (ml) = Weight (kg) × 35 Exercise Add-on (ml) = 500 ml per 30 minutes of exercise Total = Baseline + Exercise Add-on
Water Intake Example
A 70 kg person exercising 45 minutes: baseline = 70 × 35 = 2450 ml; exercise add-on = one 30-min block × 500 ml = 500 ml; total ≈ 2950 ml (about 2.95 L).
How to Use This Calculator
- Enter your body weight in kilograms.
- Enter your typical daily exercise duration in minutes.
- Select "Calculate" to see your estimated daily water target.
Limitations
- Fluid needs vary substantially with climate, altitude, sweat rate and individual health — this is a general starting point, not a precise prescription.
- Thirst and urine colour (pale yellow is a good sign) are useful everyday indicators alongside any calculated target.
- People with kidney, heart or other conditions affecting fluid balance should follow their doctor's specific guidance rather than a general calculator.