EFSA set adequate intakes of total water of 2.0 litres a day for adult women and 2.5 litres a day for adult men, counting water from drinks and food[1]. In pregnancy it adds 300 mL a day[1]. The NHS advises aiming for 6 to 8 cups or glasses of fluid a day[2].
How the water calculator works
The calculator shows the European Food Safety Authority's adequate intake of total water for your sex: 2.0 litres a day for women and 2.5 litres a day for men[1]. If you choose pregnant, it adds the 300 mL a day EFSA proposes in proportion to the extra energy needed[1].
"Total water" means all the water you take in, from drinking water, other drinks and the moisture in food. Fruit, vegetables, soups, yoghurt and cooked grains all contribute, so your drinks alone can be less than the total.
Water, drinks and hydration day to day
The NHS puts the practical message simply: aim for 6 to 8 cups or glasses of fluid a day[2]. Water, lower-fat milk and sugar-free drinks, including tea and coffee, all count. You need more in hot weather, when you are physically active, and when you are unwell with a fever, vomiting or diarrhoea.
Signs you may need more
Thirst, dark yellow or strong-smelling urine, passing little urine, headaches and tiredness can all be signs that you are not drinking enough. Pale straw-coloured urine is a useful everyday check.
When to get advice
Some people need a different fluid target: people with heart failure or kidney disease may be told to limit fluids, and older adults can lose their sense of thirst. If you have a medical condition, follow the advice of your doctor or dietitian rather than a general target.
Book a video, phone or in-person session with a professional from our network. Your result can be attached so you do not start from scratch.
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Frequently asked questions
How much water should I drink a day?
EFSA's adequate intakes of total water are 2.0 litres a day for women and 2.5 litres a day for men, including water from food[1]. The NHS suggests 6 to 8 cups or glasses of fluid a day[2].
Do tea and coffee count?
Yes. The NHS counts tea and coffee towards your daily fluid[2].
How much more water do I need when pregnant?
EFSA proposes the same intake as for non-pregnant women plus 300 mL a day[1].
Can you drink too much water?
Yes, although it is rare in healthy people. Very large amounts over a short time can upset the body's sodium balance, which is why endurance athletes are advised to drink to thirst.
Does the calculator store my data?
No. The result is calculated in your browser.
Sources and citations
Every figure on this page was read on the publisher's own page. Where a country or body does not publish a figure we say so instead of estimating.
- European Food Safety Authority (EFSA), Scientific Opinion on Dietary Reference Values for water (2010)
- NHS (UK National Health Service), Water, drinks and hydration (reviewed 17 May 2023)
