Estimate how much you should drink each day, based on official guidance and adjusted for your weight, how much you exercise and whether it’s hot.
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What the guidance says
- The European Food Safety Authority recommends about 2.0 litres of total water a day for women and 2.5 litres for men, from drinks and food combined. About 20% usually comes from food.
- The NHS suggests 6 to 8 cups or glasses of fluid a day.
Water, lower-fat milk, tea, coffee and sugar-free drinks all count. You need more in hot weather, when exercising, and if you’re pregnant or breastfeeding.
Worked examples
A 68 kg woman who exercises for 30 minutes
About 2.2 litres of drinks a day, roughly 9 glasses.
The same person on a hot day
Adding heat raises the estimate to about 2.7 litres. Drink regularly through the day rather than all at once.
Signs you need to drink more
- Dark yellow, strong-smelling pee: pale straw colour is a good sign.
- Feeling thirsty, tired or light-headed.
- Headaches or a dry mouth.
It’s possible, though rare, to drink too much. If you have kidney, heart or liver problems, follow your doctor’s advice on fluid limits.
Frequently asked questions
How much water should I drink a day?
For most adults, about 1.6 to 2 litres of drinks a day, more if you’re active or it’s hot. That’s roughly 6 to 8 glasses.
Do tea and coffee count?
Yes. They count towards your fluid intake, though it’s best not to rely on caffeinated drinks alone.
Is 3 litres a day too much?
Not for most healthy adults, especially if active. Very large amounts in a short time can be dangerous.
How do I know if I'm drinking enough?
Pale yellow pee and rarely feeling thirsty are good signs.
Sources
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