Health tools
Water Intake Calculator
Get a daily hydration target based on body weight and activity level.
Baseline uses 35 ml per kg body weight, plus an activity bonus. Results update automatically.
Enter a valid body weight and activity level to estimate daily fluid needs.
How this estimate works
A common starting point is about 30–35 ml of fluid per kilogram of body weight per day. Active people often need more to replace sweat and support recovery.
- • Base intake = weight (kg) × 35 ml
- • Activity bonus adds 0–1,000 ml depending on exercise level
- • Hot climates, illness, or pregnancy may require more fluids
Thirst, urine color, and how you feel are practical day-to-day guides. People with certain medical conditions may need limits set by their clinician.
These calculators are for educational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. Read our medical disclaimer.
Frequently asked questions
- How much water should I drink per day?
- Needs vary, but a common estimate is about 30–35 ml per kilogram of body weight daily, with extra fluids for higher activity levels.
- Does coffee or tea count toward hydration?
- Most beverages and water-rich foods contribute to total fluid intake. Plain water is often the simplest choice, but other fluids count too.
- Can you drink too much water?
- Excessive fluid intake can be harmful in some medical conditions. Follow guidance from a healthcare professional if you have kidney, heart, or fluid-restriction concerns.