Hydration calculator
Estimate how much water you need today, based on your body weight, activity, the weather and your altitude.
Minutes of exercise, then how hard. Light is a walk, moderate a jog or cycling, hard a run or sport.
Height above sea level. Leave at 0 if you live near the coast.
Enter your weight to see an estimate.
- Everyday baseline–
- Exercise–
- Warm weather–
- Altitude–
Sip steadily through the day rather than drinking a lot at once. If you have kidney, heart or liver conditions, or have been told to limit fluids, ask your clinician before using this number.
This is a general estimate, not medical advice. Food and other drinks also count toward your fluid intake, and needs vary from person to person.
Talk to your physician. Use this number as a starting point for an informed discussion with your physician. It is not a substitute for medical advice.
Sources and how we calculate this. For context, the Institute of Medicine’s adequate intake for total water, from drinks and food together, is 2.7 L a day for women and 3.7 L for men aged 19 to 30 (Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate, 2005). Those values cover healthy, sedentary people in mild weather. The baseline of 33 ml per kg and the adjustments for exercise, heat and altitude are our own general estimates, not clinical standards.