Water Intake Calculator
Daily fluid target adjusted for body weight, activity and climate.
General guidance for healthy adults. Kidney and heart conditions change fluid requirements.
How it works
The baseline is around 30-35 ml per kilogram of body weight, plus roughly 500 ml per hour of exercise, with more in heat.
Food contributes about 20% of total fluid intake, and every drink counts — including tea and coffee, whose mild diuretic effect does not offset the fluid they contain. Thirst and urine colour are better day-to-day guides than any formula.