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EFSA retningslinjer
Daglig Vandindtag Beregner: Hvor Meget Vand Skal Jeg Drikke Om Dagen?
Personaliserede resultater baseret på kropsvægt, alder og aktivitetsniveau
2 L
2000 mL / 68 oz / 8 cups
2.5 L
2500 mL / 85 oz / 11 cups
Den Europæiske Fødevaresikkerhedsautoritet (EFSA)
Beregn dit vandindtag
Anbefalet daglig vandindtag
— L
(— mL / — cups)
EFSA retningslinjer
2 L
2000 mL/day · Women
2.5 L
2500 mL/day · Men
Source: Den Europæiske Fødevaresikkerhedsautoritet (EFSA)
These are total water intake recommendations from all sources (drinking water + beverages + water from food). Individual needs vary based on weight, age, climate, and health status.
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The recommended daily water intake is 2 L (2000 mL) for women and 2.5 L (2500 mL) for men, according to Den Europæiske Fødevaresikkerhedsautoritet (EFSA) (EFSA retningslinjer). These values represent total water from all sources including drinking water, beverages, and food.
Women should drink approximately 2 liters (2000 mL or 68 oz) of water per day based on EFSA retningslinjer from Den Europæiske Fødevaresikkerhedsautoritet (EFSA). This is total water including food moisture. Actively exercising women may need 0.5–1 L more.
Men should drink approximately 2.5 liters (2500 mL or 85 oz) of water per day based on EFSA retningslinjer from Den Europæiske Fødevaresikkerhedsautoritet (EFSA). This is total water including food moisture. Actively exercising men may need 0.5–1.5 L more.
A common evidence-based formula is 30–35 mL per kilogram of body weight per day. For example, a 70 kg person would need approximately 2,100–2,450 mL (2.1–2.45 L) of water. Use our calculator above for a personalised result based on your weight, age, sex, and activity level.
Use the calculator at the top of this page. Enter your body weight, age, sex, and activity level. The formula applies EFSA retningslinjer base values from Den Europæiske Fødevaresikkerhedsautoritet (EFSA) and adjusts for your individual characteristics.
A general rule is 30–35 mL per kg of body weight. For a 60 kg person this equals 1.8–2.1 L/day; for an 80 kg person, 2.4–2.8 L/day. Our calculator applies this formula adjusted for sex, age, and activity.
Den Europæiske Fødevaresikkerhedsautoritet (EFSA) recommends 2 L for women and 2.5 L for men. The US IOM/NASEM recommends 2.7 L for women and 3.7 L for men (total water). The difference reflects that EFSA retningslinjer values represent drinking water needs, while IOM values include all fluid sources. Both are evidence-based.
Drinking water can support weight management. Water has zero calories, increases satiety, and may temporarily boost metabolism. Drinking 500 mL before meals has been shown in studies to reduce caloric intake. However, water alone does not cause fat loss — it supports a healthy diet and exercise plan.
Yes. Drinking excessive amounts of water in a short period can cause hyponatraemia (dangerously low blood sodium). This is rare in everyday life but can occur during endurance events if fluid intake far exceeds sweat loss. Healthy adults should not consume more than 1 L per hour over extended periods.
Common signs of dehydration include: dark yellow urine, decreased urine output, dry mouth and lips, fatigue, dizziness, headache, reduced concentration, and in severe cases, rapid heartbeat and low blood pressure. Mild dehydration (1–2% body weight) already impairs cognitive and physical performance.
During moderate exercise, aim for 500–750 mL/hour (about 150–250 mL every 15–20 minutes). For high-intensity or prolonged exercise (more than 60 minutes), consider electrolyte replacement as well. Pre-hydrate with 400–600 mL 2 hours before exercise.
Yes. Coffee and tea contain significant amounts of water and contribute to daily hydration. Despite the mild diuretic effect of caffeine, moderate consumption (up to 4 cups/day) provides a net positive contribution to fluid balance. Den Europæiske Fødevaresikkerhedsautoritet (EFSA) considers all beverages to count toward total water intake.
Older adults (65+) should maintain the same base intake of 2 L for women and 2.5 L for men, but may need reminders as the thirst sensation decreases with age. Regular sipping throughout the day is recommended rather than waiting until thirsty.
Hot and humid climates increase sweat losses and may require 0.5–1.5 L additional water intake beyond baseline recommendations. Working or exercising outdoors in high temperatures can increase fluid needs by 2–3 L per hour. Adjust intake based on sweat rate and environmental conditions.
Both timing approaches work. Drinking water before meals can increase satiety and reduce caloric intake. Drinking water with meals supports digestion. Drinking water after meals helps with nutrient absorption. The most important factor is meeting total daily intake, regardless of timing.
Children aged 4–8 need approximately 1.2–1.6 L/day; ages 9–13 need 1.6–2.0 L/day; teenagers need 2.0–2.5 L/day depending on sex and activity. These values are from Den Europæiske Fødevaresikkerhedsautoritet (EFSA). Children are more susceptible to dehydration than adults.
There is no single optimal time. Many experts recommend drinking a glass of water upon waking, before each meal, and before bed. Distribute intake throughout the day rather than consuming large amounts at once. The body can only absorb approximately 800–1000 mL per hour.
Food contributes approximately 20% of daily water intake for most adults. Fruits and vegetables have high water content: cucumbers (97%), lettuce (96%), tomatoes (95%), watermelon (92%). Eating a diet rich in fresh produce can meaningfully contribute to hydration.
Alcohol is a diuretic — it inhibits the hormone that controls urine production (ADH), causing increased fluid loss. For every 1 gram of alcohol consumed, approximately 10 mL of additional urine is produced. Drinking a glass of water between each alcoholic drink helps offset this effect.
The 8×8 rule (eight 8-oz glasses, or about 1.9 L/day) is a popular simplification but not based on a specific scientific recommendation. It is below the EFSA retningslinjer value of 2 L for women and 2.5 L for men. Use the guidelines from Den Europæiske Fødevaresikkerhedsautoritet (EFSA) as your reference.
Pregnant women need approximately 2.3–2.4 L/day (total water), representing an increase of 300–500 mL above non-pregnant recommendations. Increased blood volume, amniotic fluid production, and foetal needs all raise hydration requirements. Consult your midwife or doctor for individual advice.
Breastfeeding women need approximately 2.7–3.1 L/day to support milk production. Each litre of breast milk produced requires approximately 900 mL of water from the mother. Many guidelines recommend drinking a glass of water each time you breastfeed as a reminder strategy.
Yes. At altitude above 2,500 metres, the body loses more water through increased breathing rate and respiratory water loss. Many people also experience reduced thirst sensation at altitude. Increasing water intake by 0.5–1 L/day is recommended above 3,000 metres elevation.
Adequate hydration supports: better physical performance, improved concentration and mood, healthy kidney function, regular bowel movements, temperature regulation, nutrient transport, joint lubrication, and healthy skin appearance. Chronic mild dehydration is associated with increased risk of kidney stones and urinary tract infections.
Check urine colour — pale yellow (straw-coloured) indicates good hydration; dark yellow or amber indicates dehydration. Other indicators: urine frequency (6–8 times per day is healthy), absence of thirst, normal energy levels, and moist mouth. Use our calculator to determine your personalised daily target.
Yes. Muscle tissue is approximately 75% water, while adipose (fat) tissue is approximately 10% water. Therefore, people with higher lean body mass (athletes, bodybuilders) have proportionally higher water content and may require slightly more daily water intake.
Yes. Sparkling water is equally hydrating as still water. The carbonation does not affect its hydrating properties. However, people with acid reflux or irritable bowel syndrome may find sparkling water less comfortable. Plain water (still or sparkling) is superior to sweetened sparkling beverages.
Athletes typically need 2.5–5 L or more per day depending on sport, training intensity, duration, and climate. Endurance athletes (marathoners, triathletes) may need 6–10 L on race days. Sweat rate testing can help calculate individual fluid replacement needs.
The ketogenic diet can initially increase water and electrolyte losses as glycogen stores are depleted. Each gram of glycogen stored in muscles binds approximately 3 g of water. When glycogen is used up, this water is excreted, leading to increased urination. Increasing water intake by 0.5–1 L/day during the initial keto adaptation phase is recommended.
Creatine supplementation is associated with increased intracellular water retention in muscle tissue. Users are typically advised to increase water intake by 500–1000 mL/day above normal recommendations to support this process and maintain kidney health.
Electrolytes (sodium, potassium, magnesium, chloride) regulate the movement of water in and out of cells. During prolonged sweating, electrolyte replacement is as important as fluid replacement. Drinking only water without electrolytes during very long exercise sessions can dilute blood sodium levels (hyponatraemia).
Drink 400–600 mL (13–20 oz) of water 2 hours before exercise. Consume another 150–250 mL (5–8 oz) 15–20 minutes before starting. This allows time for absorption and pre-exercise urination without beginning exercise in a hyperhydrated state.
During exercise lasting less than 60 minutes, drink 150–250 mL every 15–20 minutes. For longer sessions, aim for 500–750 mL per hour and consider electrolyte drinks if sweating heavily. Avoid drinking so much that you feel full or experience gastrointestinal discomfort.
After exercise, drink 1.5 L of fluid for every kilogram of body weight lost during exercise (weigh yourself before and after). This replaces sweat losses plus accounts for continued losses during recovery. Including sodium in post-exercise fluids enhances rehydration.
Chronic dehydration increases the concentration of urine and the risk of kidney stones (particularly calcium oxalate stones). It also increases the risk of urinary tract infections. Maintaining adequate hydration is one of the most effective lifestyle factors for preventing kidney stones.
Adequate hydration supports skin health by maintaining elasticity and moisture. Dehydration causes dry skin, reduced skin elasticity, and can worsen conditions like eczema. However, drinking excess water beyond recommended amounts does not significantly improve skin appearance in well-hydrated individuals.
Water intoxication (hyponatraemia) occurs when water intake dilutes blood sodium to dangerously low levels. Symptoms include nausea, headache, confusion, and in severe cases, seizures or coma. It can occur during endurance events when athletes drink only plain water without replacing sodium. Risk is very low in normal daily life.
High dietary fibre increases water requirements. Fibre absorbs water in the gut to form a soft gel that moves through the digestive tract. Without adequate water, high fibre intake can cause constipation. For every 5 g of additional dietary fibre, drink an additional 100–200 mL of water.
Drinking water immediately upon waking rehydrates the body after 7–8 hours without fluid intake and can help with alertness and bowel regularity. Starting the day with a glass of water (200–400 mL) is a healthy habit recommended by most nutrition guidelines.
Beyond drinking water: eat water-rich foods (fruits and vegetables), drink herbal teas, consume broths and soups, eat foods with high water content (yoghurt, smoothies), drink milk (which is approximately 87% water), and use sparkling water or flavoured water (without added sugar) as alternatives.
Some medications increase fluid requirements: diuretics, lithium, certain antipsychotics, and some diabetes medications. Others may affect kidney function or electrolyte balance. If you are on regular medication, consult your pharmacist or doctor about any effect on your hydration needs.
In hot weather (above 30°C/86°F), increase water intake by 0.5–1 L for every hour spent outdoors. In extreme heat (above 40°C/104°F) with physical activity, fluid needs can increase to 1–2 L per hour. Monitor urine colour and do not wait until thirsty to drink.
Even mild dehydration (1–2% of body weight) is associated with reduced concentration, impaired short-term memory, slower reaction time, increased perception of task difficulty, and worse mood. Proper hydration supports optimal brain function throughout the day.
Yes. Dehydration is a well-recognised trigger for tension headaches and migraines. The exact mechanism is not fully understood, but brain tissue is affected by blood volume changes. Drinking water at the onset of a headache is often an effective first-line response.
Drinking 500 mL of water has been shown to increase metabolic rate by approximately 24–30% for 30–60 minutes in some studies. This is largely a thermogenic effect as the body heats the cold water to body temperature. The effect is modest and not a weight loss strategy by itself.
Adequate hydration helps maintain healthy blood viscosity (thickness) and blood volume, supporting normal blood pressure. Dehydration can cause blood to thicken and reduce blood volume, making the heart work harder. Some studies associate chronic dehydration with increased risk of hypertension.
Tap water quality in most European countries is very high — among the safest in the world. European tap water is regulated under the EU Drinking Water Directive which sets strict limits for over 50 chemical parameters. In most EU capitals and cities, tap water is safe to drink directly without filtering.
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