The Water Intake Calculator tells you exactly how much water you should drink per day based on your weight, activity level and climate. Proper hydration affects energy, concentration, metabolism and almost every function in the body.
Frequently Asked Questions
How much water should I drink per day?
A common guideline is 8 glasses (2 litres) per day, but it varies by body weight and activity. A better rule is 35ml per kg of bodyweight — so a 70kg person needs about 2.5 litres.
Does coffee and tea count toward hydration?
Yes — despite the mild diuretic effect, caffeinated drinks still contribute to your daily fluid intake. Plain water is still best.
How do I know if I'm dehydrated?
Dark yellow urine, headaches, fatigue, dry mouth and reduced concentration are common signs. Pale yellow urine indicates good hydration.
Should I drink more water when exercising?
Yes — add 500ml–1 litre per hour of exercise, more in hot weather. Drink before, during and after workouts.