Water Intake Calculator
Estimate your recommended daily water intake from your body weight and activity level, in liters and cups.
Optional: estimate your personal sweat rate
For a more personal exercise estimate, weigh immediately before and after a session and include any fluid consumed during it. This simple method assumes no bathroom break during the session.
Personal sweat rate: optional.
Avoid excessive water intake: drinking far beyond your needs can cause hyponatremia (dangerously low blood sodium). If you have kidney disease or heart failure, follow your clinician’s fluid advice. Thirst + pale-yellow urine are the practical guides.
Calorie targets? BMR calculator · activity burn: Calories burned · sleep recovery: Sleep calculator.
How to use the range
Start with the 30–40 ml/kg total-water heuristic. The main result subtracts the roughly 20% commonly supplied by food and shows fluids to drink. Exercise adds a broad range unless you enter personal sweat-rate data.
FAQ
How much water should I drink?
Common heuristics give 30–40 ml/kg of total water per day. About 20% may come from food, so the main result estimates the remaining fluids to drink.
Does exercise change the estimate?
Yes. Without personal sweat data, this tool adds a broad 400–800 ml per hour of exercise range.
How does the personal sweat-rate estimate work?
Enter exercise duration, body weight immediately before and after the session, and any fluid consumed during it. The calculator estimates sweat loss per hour; the simple method assumes no bathroom break during the session.
Can drinking too much water be harmful?
Yes. Excessive water intake can cause hyponatremia, or dangerously low blood sodium. If you have kidney disease or heart failure, follow your clinician’s fluid advice.
What practical signs should I use?
Thirst and pale-yellow urine are practical day-to-day guides. Individual needs vary with weather, health, pregnancy, diet and medications.
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