Water Intake Calculator
Estimate daily fluid needs from body weight, exercise habits, and hot weather. Includes all beverages and water-rich foods.
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Results
Estimated daily fluids
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Base (35 ml per kg)—
Activity bonus—
Heat bonus—
Frequently asked questions
Does this count only water?
No — the estimate includes fluids from all beverages and water-rich foods (fruit, soup, etc.). You do not need to drink the full amount as plain water alone.
How much water do I need per day?
Needs vary by body size, sweat, climate, and activity. This tool uses ~35 ml per kg body weight as a baseline, then adds bonuses for exercise and hot weather. Thirst, urine color, and your clinician's advice also matter.
When should I drink more?
Increase fluids before outdoor work or exercise in heat, during illness with fever, or when urine is dark. Seek urgent care for signs of heat stroke or severe dehydration.