Calculate your daily water needs based on weight and activity level.
The Water Needs Calculator calculates your daily hydration needs based on weight, activity level, and climate. Adequate hydration is important for metabolism, kidney function, and brain activity.
The calculator is completely free, works directly in your browser, and does not store personal information. All calculators on this site are based on up-to-date information.
Water needs (ml/day) = weight (kg) × 30–35 ml. Add exercise: +500–1000 ml per hour of exercise.
Enter your measurements into the calculator fields and press the calculate button – the result will be displayed immediately. You can try different values to compare various scenarios.
75 kg, moderate exercise 1 h/day → 75 × 33 = 2,475 ml + 700 ml = 3,175 ml ≈ 3.2 liters/day.
The result is an estimate – for precise clinical measurements, consult a healthcare professional.
The calculator is suitable for self-monitoring health, planning workouts, and general health literacy. Tracking values over time provides valuable information about changes in the body.
Remember that a single measurement does not tell the whole story – what matters more is the direction and trend over multiple measurement periods.
Calculate your daily water needs based on weight and activity. Fill in the requested information in the form, and the water needs calculator will show the result immediately.
Yes, the water needs calculator is completely free and does not require registration. All FiksuLaskuri health calculators are free of charge.
No. The calculations are done entirely in your browser and the data you enter is not sent or stored on the server.
No. The water requirement calculator is a rough guide, not a medical diagnosis. For health-related decisions, it is advisable to consult a healthcare professional.
Yes – at the bottom of the page, you can see other calculators related to the same topic that may also interest you.