Water Intake Calculator

Water keeps your body temperature steady, carries nutrients, cushions joints and helps your kidneys remove waste. How much you need depends on your size, how much you sweat and how hot it is.

A common rule of thumb is about 35 ml of water per kg of body weight a day, plus extra when you exercise or when it is hot. This calculator uses that rule to give you a daily target.

How to use the water intake calculator

1. Enter your weight in kg.
2. Enter how many minutes you exercise on a normal day.
3. Choose hot or humid if it is summer or you work in the heat.

You will see how much to drink in litres and in 250 ml glasses.

How it is calculated

Water (ml) = Weight (kg) × 35
           + 350 ml for every 30 minutes of exercise
           + 500 ml in hot or humid weather

Example

You weigh 70 kg and exercise for 30 minutes a day in normal weather.

• For your weight: 70 × 35 = 2,450 ml
• For exercise: 350 ml
• Total: 2.8 litres a day, about 11 glasses of 250 ml

Someone who weighs 60 kg, doesn't exercise and lives through a hot summer needs 2,100 + 500 = 2.6 litres, about 10 glasses.

For comparison, the European Food Safety Authority suggests about 2.0 litres of total water a day for women and 2.5 litres for men, from all drinks and food together, in a mild climate.

What counts as water

All drinks count: plain water, milk, buttermilk (chaas), nimbu paani, coconut water, tea, coffee and soups. Watery foods such as dal, curd, cucumber, watermelon and fruit also add some. Sugary drinks and packaged juices count too, but they add a lot of calories, so keep them small.

Signs you are drinking enough

• Your urine is pale yellow for most of the day.
• You rarely feel very thirsty.
• You don't get headaches or feel tired from the heat.

Be careful if

• You have kidney disease, heart failure or liver disease. Your doctor may limit how much you drink. Follow their advice, not this calculator.
• You drink far too much in a short time. Drinking many litres within a few hours, especially during long exercise, can make the salt level in your blood fall dangerously. When sweating a lot for hours, use ORS or a drink with salt.