Daily Water Intake Calculator
Calculate your recommended daily water intake based on body weight and activity level.
How to use this tool
- Enter body weight and activity level in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your water per day and the full breakdown beneath it.
A common guideline is 35 ml of water per kg of body weight per day, adjusted upward for high activity. This calculator gives a practical daily target.
Frequently asked questions
- How much water should I drink per day?
- The NHS recommends 6–8 cups (1.5–2 L) daily. The 35 ml/kg rule adjusts this for body size and is widely used by dietitians.
- Does coffee or tea count towards water intake?
- Yes — caffeinated drinks count towards hydration despite mild diuretic effects. Fruit and vegetables also contribute significant water.