Water Intake Calculator

How much water should you really drink?

The old "eight glasses a day" rule was never personalised. A better estimate scales with your body weight and how active you are. This calculator uses roughly 33 ml per kilogram of body weight, then adds for activity, to give a daily target in litres, ounces and cups. Food and other drinks count too, so treat it as a guide rather than a quota — and always drink to thirst in heat or during exercise.

Eat and drink for steady energy

Hydration is one piece of feeling well. Our Nutrition guides cover anti-inflammatory eating, gut health and steady energy, all in plain English.