Water Intake Calculator

Calculate your recommended daily water intake based on weight, activity level, and climate. Stay properly hydrated with personalized recommendations.

How it works

Daily water (ml) = weight(kg) × 33, + 500 ml per hour of exercise, + 500 ml in hot or humid conditions.

Worked example

A 70 kg person needs about 2.3 litres as a baseline. Add a one-hour gym session and that rises to roughly 2.8 litres, or 3.3 litres in summer heat.

Frequently asked questions

Do coffee and tea count?

Yes. Caffeinated drinks are mildly diuretic but still net-hydrating, and food supplies around 20% of total intake. Only alcohol reliably works against your total.

How do I know if I'm hydrated?

Pale straw-coloured urine and urinating every 3–4 hours is the simplest check. Dark yellow urine, headache or dry mouth suggest you are behind.

Can you drink too much water?

Rarely, but yes. Drinking several litres in a short window can dilute blood sodium (hyponatraemia). Spread intake across the day and add electrolytes for long endurance efforts.