Daily water intake calculator

The range comes from two published reference rates: 25 to 35 ml of fluid per kilogram of body weight per day, the baseline the British Dietetic Association quotes, plus 0.4 to 0.8 litres per hour of sweating activity from the American College of Sports Medicine guidance on replacing exercise losses. Both rates are ranges on purpose: how much you actually need moves with heat, humidity, illness, pregnancy, and the food you eat, which carries fluid too. The estimate counts total fluid, not glasses of plain water, and it is a general guide for a healthy adult, not advice for kidney, heart, or other conditions that change fluid needs. Nothing here is medical advice.