Water Intake Calculator
Work out how much water your body needs each day based on your weight, activity and the heat. You also get a schedule for spreading it across the day, plus tips for fasting in Ramadan.
Calculator
This result is an educational estimate, not a diagnosis. Ask your doctor to interpret it.
What does this mean?
Advice for you
How does this calculator work?
The calculator starts with 35 ml per kilogram of body weight, the rule of thumb used clinically to estimate adult needs. We then add 0.5–1 litre for activity and 0.5–1 litre for heat, because sweating in a Gulf climate can cost you more than an extra litre a day.
For comparison, the European Food Safety Authority recommends a total of 2 litres a day for women and 2.5 litres for men from all sources in mild conditions.
Scientific sources
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on Dietary Reference Values for water. EFSA Journal. 2010;8(3):1459.
- Sawka MN, et al. Human water needs. Nutr Rev. 2005;63(6 Pt 2):S30–S39.
Frequently asked questions
Do tea and coffee count towards water?
Partly, yes, but plain water is the best choice, and lots of caffeine can make you urinate more.
Can I drink too much water?
Rarely in healthy people, but drinking very large amounts in a short time can lower your sodium. Spread it across the day.
How can I avoid thirst in Ramadan?
Drink two glasses at iftar, then a glass every hour until suhoor, and avoid salty food at suhoor.
Do pregnant women need more water?
Yes — pregnant women usually need about 300 ml extra a day, and breastfeeding women about 700 ml.