Water Intake Calculator
Daily hydration target scaled by weight and activity.
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About this calculator
Hydration needs vary with sweat rate, diet and environment far more than any formula captures. These estimates anchor a starting point; thirst plus urine colour remain the best real-time gauges.
Formula
Baseline ≈ 33 ml/kg; +350 ml per 30 min exercise; ± climate adjustment.
Health metrics are informational estimates and are not a medical diagnosis.
Frequently Asked Questions
Does tea/coffee count?
Yes — the diuretic effect of moderate caffeine is smaller than the fluid it delivers. Soups, milk and fruit contribute too.
Can I drink too much?
Rare but real: hyponatraemia from litres beyond sweat losses without electrolytes, mostly in long endurance events.