Daily water intake calculator
Enter your age, sex and weight. The water intake 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.
Example: Age 35 years · Sex: female · Pregnancy / breastfeeding: neither · Body weight 70 kg → Fluids from drinks, DGE (liters/day): 1.41. Source: Deutsche Gesellschaft für Ernährung (DGE) – Referenzwerte: Wasser, guideline values for water intake (accessed 27 Sep 2026). Updated: .
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.
How to calculate your water intake
- Enter age and sex, and pregnancy or breastfeeding if it applies.
- Enter your body weight.
- Tick heat, exercise, fever or diarrhea if relevant – the calculator shows how much to drink per day.
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.
More health calculators: the BMR calculator for calories, the calories burned calculator for exercise and the sleep calculator for bedtime.
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
- Deutsche Gesellschaft für Ernährung (DGE) – Referenzwerte: Wasser, guideline values for water intake (accessed 27 Sep 2026)
- EFSA Journal 2010;8(3):1459: EFSA Panel on Dietetic Products, Nutrition and Allergies – Scientific Opinion on Dietary Reference Values for water
As of: · Editorial policy
Related tools
- BMI calculator (WHO categories)BMI calculator in lb and ft/in or kg and cm: your body mass index with WHO category on a colour scale, healthy weight range for your height and BMI Prime.
- Calories burned calculatorEstimate calories burned in 30 sports and activities from MET value, body weight and duration per the 2024 Compendium, in kg or lb, with a personal correction.
- Dog age calculator: dog years to human yearsHow old is your dog in human years? Uses the 16·ln(age)+31 formula (Wang et al. 2020) and the AVMA size chart, compares both and shows the senior age.
- Cat age calculator: cat years to human yearsHow old is my cat in human years? Convert cat age, kittens in months too, with the AAFP-AAHA chart and see the life stage from the 2021 AAHA/AAFP guidelines.
- Intermittent fasting calculator and timerIntermittent fasting calculator: pick your eating window start (16:8, 14:10, 18:6, 20:4) and see eating and fasting times plus a timer for the current phase.
- Online metronomeFree online metronome: 20–300 BPM, time signatures from 2/4 to 12/8, accents per beat, subdivisions and tap tempo. Sample-accurate, no app needed.
- Laundry symbols explained: read your care label and build the symbolsLaundry symbols explained: choose what your care label shows and read what washing, bleaching, drying, ironing and cleaning symbols mean. With a picture.
- Heat index calculatorHeat index calculator: enter air temperature and relative humidity for the feels-like heat by the US National Weather Service formula, with levels and a chart.
- Alcohol calorie calculatorAlcohol calorie calculator: from amount, alcohol content and sugar get calories in beer, wine or spirits, with grams of pure alcohol and a comparison table.