Daily water intake calculator

Enter your age, sex and weight. The calculator shows the adequate intake set by the European Food Safety Authority (EFSA) and, for comparison, the reference values of the German Nutrition Society (DGE). Both are guideline values for healthy people, not personal advice.

Age

years

Infants under 1 year have separate values – please ask a pediatrician.

Sex

Pregnancy / breastfeeding

Body weight

Optional – for the DGE value per kilogram of body weight (1 lb = 0.454 kg).

Heat, exercise, fever or diarrheaShows a note. The sources give no fixed extra amount, so nothing is added.

Your inputs are saved in this browser only.

Result

Fluids from drinks, DGE (liters/day): 1.41
Total water, DGE (liters/day): 2.6
of which from solid food (liters): 0.86
of which metabolic water (liters): 0.33
Total water by body weight, DGE (liters/day): 2.45
Total water, EFSA adequate intake (incl. food): 2 L; Guideline values for healthy people, not a diagnosis. This calculator does not replace medical advice – especially with heart or kidney disease, a prescribed fluid limit, for children and older adults.

How it is calculated

How much water do you need per day?

Your body gets water in three ways: from drinks, from the water in food and as metabolic water produced when nutrients are broken down. The EFSA sets an adequate intake for total water from drinks and food: 2.0 liters a day for women and 2.5 liters for men, the same for older adults. Pregnant women need 0.3 liters more, breastfeeding women 0.7 liters more.

Example: woman, 35 years, 70 kg (154 lb)

EFSA: 2.0 L total water (about 68 fl oz) – drinking water, all beverages and water from food combined; EFSA gives no breakdown.
DGE: drinks 1.41 L, solid food 0.86 L, metabolic water 0.33 L, 2.6 L in total.
By body weight (DGE): 35 ml per kg × 70 kg = 2,450 ml = 2.45 L total water.

Why do EFSA and DGE differ?

The EFSA values from 2010 cover drinking water, all beverages and food moisture and differ by sex. The DGE table was derived in 2000, includes metabolic water and does not differ by sex. They rest on different data and methods but agree on the order of magnitude for drinks, so the calculator shows both side by side.

Heat and exercise

The values apply to moderate temperatures and average activity. Heat, exercise, dry air, fever, vomiting or diarrhea raise your needs. How much depends on how much and how long you sweat; neither EFSA nor DGE gives a flat extra amount, so this calculator adds nothing and only shows a note.

Limits

The values are for healthy people. With heart or kidney disease, a doctor may set a lower or higher fluid target. Older adults often feel less thirsty and should drink deliberately. Infants under one year have separate values. This calculator does not replace medical advice.

Frequently asked questions

How much water should an adult drink a day?

According to the DGE, about 1.4–1.5 liters via drinks (age group 25–50: 1,410 ml). Additional water comes from food and metabolism.

Do coffee and tea count?

The EFSA values explicitly include beverages of all kinds. Water and unsweetened tea are the best choices.

How much water do pregnant and breastfeeding women need?

EFSA: 2.3 L (pregnant) and 2.7 L (breastfeeding) of total water, i.e. 0.3 L and 0.7 L more than non-pregnant women.

Do I need more water during exercise or heat?

Yes. The sources give no fixed extra amount because it depends on how much you sweat. Drink more according to thirst.

Can you drink too much water?

Very large amounts in a short time can be dangerous. If you have a medical fluid limit, follow your doctor’s advice.

Sources and legal basis

As of: 27 September 2026