Daily Water Intake for an 80 kg Active Person
An active 80 kg person typically needs approximately 3.0–3.5 litres of water daily to stay properly hydrated.
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.
Physical activity significantly raises your fluid needs — calculate your daily hydration target based on your body weight and lifestyle.
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.