Water Intake Calculator
Calculate your daily water intake based on body weight and activity level. Free online hydration calculator.
Enter your weight and height
How It Works
- Enter your body weight.
- Select your activity level (sedentary, moderate, or active).
- The calculator applies the 35-40 ml per kg guideline adjusted for activity.
- Your personalised daily water target is shown in millilitres and litres.
- Spread your intake throughout the day - do not drink it all at once.
Formula
Base (sedentary): 35 ml x body weight (kg)
Moderate activity: 40 ml x body weight (kg)
Active/sport: 45 ml x body weight (kg)Example
Input: Weight: 70 kg | Activity: Moderate
Result: Daily water target: ~2,800 ml (2.8 L)
Approx. 9-10 glasses (280 ml each)
FAQ
The base is 35 ml per kilogram of body weight for sedentary individuals. Activity increases the requirement to around 40 ml/kg (moderate) or 45 ml/kg (active).
No. The calculator estimates drinking water only. About 20% of daily water intake typically comes from food.
No. All calculations run entirely in your browser. No personal data is ever sent to a server.
No. Spread your water intake evenly throughout the day. Drinking too much at once can be harmful. Frequent small sips are best.