How Much Water per Day? Fluid Intake According to the DGE
The German Nutrition Society's reference values for drinks and water by age, what increases your needs and how the calculator derives your daily fluid intake.
Health & Body2 linked calculatorsReading time: 5 min.
Guidance, not a diagnosis
This article explains reference values and where they come from. It does not replace a medical examination or advice. Different values often apply if you have symptoms, are pregnant, for children and for pre-existing conditions: in that case, talk to your doctor.
The familiar rule of thumb of two to three litres a day mixes two things: the water you drink and the water that comes in with food. The German Nutrition Society (DGE) separates the two and gives reference values for each age group.
Key takeaways
- According to the DGE, adults aged 25 to 51 should drink about 1.4 litres a day.
- Roughly a third of water needs is covered by solid food, more than half by drinks.
- Heat, exercise, fever, vomiting and diarrhoea increase your needs.
- The best thirst quenchers are water and unsweetened herbal or fruit teas.
Reference values by age
The table shows the DGE reference values for intake from drinks and for total water intake from drinks, solid food and the water produced by metabolism. The last column is intake from drinks and solid food per kilogram of body weight.
| Age | Drinks | Total water | Drinks and food per kg |
|---|---|---|---|
| 1 to under 4 years | 0.8 l | 1.3 l | 95 ml |
| 4 to under 7 years | 0.9 l | 1.6 l | 75 ml |
| 7 to under 10 years | 1.0 l | 1.8 l | 60 ml |
| 10 to under 13 years | 1.2 l | 2.2 l | 50 ml |
| 13 to under 15 years | 1.3 l | 2.5 l | 40 ml |
| 15 to under 19 years | 1.5 l | 2.8 l | 40 ml |
| 19 to under 25 years | 1.5 l | 2.7 l | 35 ml |
| 25 to under 51 years | 1.4 l | 2.6 l | 35 ml |
| 51 to under 65 years | 1.2 l | 2.3 l | 30 ml |
| 65 years and older | 1.3 l | 2.3 l | 30 ml |
For pregnant women the DGE gives about 1.5 litres of drinks a day, for breastfeeding women about 1.7 litres.
Where the water comes from and where it goes
The body constantly loses water through the kidneys, the gut, the skin and breathing. The DGE describes the balance for an adult (19 to under 51 years) in an average German climate like this:
| Intake | ml per day | Output | ml per day |
|---|---|---|---|
| Drinks | 1,440 | Urine | 1,440 |
| Water in solid food | 875 | Stool | 160 |
| Oxidation water (metabolism) | 335 | Skin | 550 |
| Breathing | 500 |
Intake and output balance at 2,650 ml each. Drinks make up a good half of it.
When you should drink more
The reference values apply to normal living conditions. According to the DGE, the body needs more water mainly
- with high energy expenditure, such as heavy physical work and exercise,
- in heat and in dry, cold air,
- with a diet high in salt or protein, and with fever, vomiting or diarrhoea.
How much extra to drink when training is estimated by the fluid intake calculator for exercise.
With certain illnesses, your doctor's advice comes first
For some conditions, such as heart or kidney disease, your doctor may set a specific fluid intake. That instruction takes precedence over any general reference value.
Calculating fluid intake from body weight
For adults aged 25 to 51, the DGE gives 35 ml per kilogram of body weight for drinks and solid food together. Our calculator takes the share the DGE assigns to drinks. Example: 80 kg and 35 years give 2.80 litres of water in total; about 62% of that comes from drinks, so roughly 1.74 litres to drink.
Calculate your fluid intake
Using weight, age and activity. The exercise add-on is a labelled assumption.
What is good to drink
As thirst quenchers, the DGE recommends mineral and tap water and unsweetened herbal and fruit teas. Coffee and black tea should be drunk in moderate amounts of three to four cups a day. Sweetened drinks add energy that counts towards your calorie balance.
Frequently asked questions about fluid intake
How many litres should I drink a day?
Does water from food count?
Do coffee and tea count?
Do older people need less?
Sources
Every figure in this article comes from these primary sources or from the linked calculators, which are based on the same sources.
- German Nutrition Society (DGE): reference values for water (derived 2000) (accessed September 30, 2026)
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