How much water should you drink each day? The water intake calculator

How much water should you drink each day? The German Nutrition Society (DGE) recommends 1,410 ml from drinks per day for adults aged 25 to under 51, whilst the IQWiG suggests around 1.5 litres as a good guideline. However, your requirements depend, amongst other things, on your age, weight and state of health. The calculator shows you the appropriate guideline – and explains transparently where each figure comes from.

Fluid Intake Calculator

Select your age or life situation. The tool also calculates your body weight in kilograms and, using your training time and scales, shows how exercise makes a difference. All figures are taken from the sources listed below.

The DGE’s recommended intake levels by age

The DGE distinguishes between the different sources of water: from drinks, from solid food and as oxidised water.

These figures apply to energy intake tailored to individual needs and average living conditions; they were derived in the year 2000. The DGE provides its own figures for infants, which are not included in the calculator – different standards apply to infants and young children than to adults.

Anyone who eats less – for example, whilst on a diet or due to illness – consumes less water through food, and there is also a lack of oxidised water. In such cases, drinks are particularly important.

How much water per kilogram of body weight?

The DGE recommends 35 ml per kilogram of body weight for those aged 19 to under 51, and 30 ml for those aged 51 and over. Important: This column refers to water from both drinks and solid food combined. According to the DGE, solid food accounts for about a third of the required water intake, whilst drinks account for more than half.

An example for a 70 kg, 30-year-old: 70 × 35 ml equals 2,450 ml from drinks and food. According to the DGE guideline for this age group, 1,410 out of 2,270 ml come from drinks, i.e. 62 per cent. Applied to a weight of 70 kg, that amounts to around 1,520 ml from drinks. This is exactly how the calculator works when you enter your weight.

Exercise, hot weather, breastfeeding: when you need more

The DGE states that water requirements increase in cases of high energy expenditure, heat, dry cold air, high salt intake, as well as fever, vomiting and diarrhoea. Neither the DGE nor the IQWiG specify a fixed additional amount for hot days; according to VerbraucherService Bayern, it is perfectly fine to drink more in hot weather.

• Before exercising: drink one or two glasses of water about half an hour before you start.
• Short training sessions: For moderate exercise lasting up to an hour, it is enough to drink after your workout; for shorter sessions, water is often sufficient.
• Intense exercise lasting longer than an hour: drink regularly – depending on the intensity and the outside temperature, up to one litre per hour, in portions of 125 to 250 ml approximately every 15 to 20 minutes.
• Breastfeeding: Breastfeeding women should drink around 250 ml more; there is no recommendation for pregnant women to drink more.

The amount you lose whilst exercising ranges from a few hundred millilitres to three litres per hour. The scales provide a more precise figure: you start to feel thirsty when your body loses around 0.5 per cent of its weight in water – for someone weighing 70 kg, that’s 350 ml. From around 3 per cent, this is referred to as dehydration. You can find out more about minerals and sport in the article ‘Electrolytes no sugar’.

Is it possible to drink too much water?

Yes, if you drink it too quickly. Because the kidneys are generally very efficient, large quantities spread out over the course of the day usually do no harm. However, drinking a lot of fluid in a short space of time can upset the electrolyte balance and, in the worst case, lead to water intoxication. Older people should spread larger amounts over several hours and drink no more than 0.7 to 1 litre per hour.

According to VerbraucherService Bayern, recommendations to drink 2 to 4 litres a day for the sake of your figure and skin are not scientifically substantiated. In cases of heart or kidney failure, fluid requirements can vary greatly – in such cases, your doctor will advise you. The article ‘Not drinking enough’ explains how you can tell if you haven’t had enough to drink.

What counts towards your fluid intake?

According to the IQWiG, the best choices for everyday consumption are water and unsweetened, non-alcoholic drinks such as fruit and herbal teas, as well as juice spritzers containing little juice and plenty of water. Tap water in Germany is safe to drink.

Coffee, black tea and green tea also count, as caffeine has only a slight diuretic effect – but you should not rely solely on caffeinated drinks to meet your entire fluid intake. The DGE recommends moderate amounts of 3 to 4 cups of coffee and black tea. Alcoholic drinks are not thirst-quenchers.

Our Still and Sparkling ranges are table waters in 0.33-litre cans. Whether still or sparkling – the difference lies in whether it’s still or sparkling.

How to meet your fluid intake target

• Link drinking to specific times, for example whilst eating, on the phone or after your lunch break.
• Pour your daily amount into jugs or bottles in the morning – that way you can see how much you’ve already drunk.
• Drink throughout the day, about one glass every two hours; you can’t drink in advance.
• Vary the drinks you have, or keep a record of how much you drink using an app or a fitness tracker.

Your morning routine shows how drinking a glass of water can become a habit. The ‘Drinking Water’ page brings together everything to do with drinking.

Frequently Asked Questions

Sources

1. German Nutrition Society: Reference values for nutrient intake: Water, 2000 edition, accessed 16 September 2026. dge.de
2. Institute for Quality and Efficiency in Health Care (IQWiG), gesundheitsinformation.de: Drinking enough in everyday life: tips and advice, 18 October 2023. gesundheitsinformation.de
3. VerbraucherService Bayern im KDFB e. V.: Recommendations on fluid intake – a critical look, 25 August 2021. verbraucherservice-bayern.de
4. Hessen Consumer Advice Centre: Specialised sports drinks are unnecessary, as at 27 April 2022. verbraucherzentrale-hessen.de
5. Federal Institute for Public Health (BIÖG), ‘Staying Active and Healthy as You Age’ portal: Drinking enough and drinking the right things: fluid intake and recommended drinks, accessed 16 September 2026. gesund-aktiv-aelter-werden.de
6. ACQUA REAPER: Product labels – Still and Sparkling, 26/08.
7. ACQUA REAPER: Product specifications, 14 September 26.