Daily Water Calculator
Calculate how much water you should drink daily.
Daily water calculator: personalized hydration for your body
Adequate hydration is essential for optimal functioning of the human body, which is composed of between 55% and 75% water. Even mild dehydration (1-2% of body weight) can cause fatigue, headaches, and reduced performance.
Our calculator uses the European Food Safety Authority (EFSA) recommendation of approximately 33 ml of water per kilogram of body weight as a base, with adjustments for physical activity and climate.
Approximately 20-30% of daily water comes from food, especially fruits and vegetables with high water content. Beverages like tea and coffee also count. The classic recommendation of "8 glasses a day" is a good starting point but does not adjust to individual needs.
Frequently asked questions
Do coffee and tea count as water?
Yes, caffeinated beverages contribute to hydration. Although caffeine has a slight diuretic effect, the water contained in these beverages far outweighs the loss. Recent studies have shown that moderate coffee consumption (3-4 cups per day) does not cause dehydration. Only alcoholic beverages have a significant net negative diuretic effect.
Can you drink too much water?
Yes, although it's rare. Hyponatremia (drinking excess water that dilutes blood sodium) can occur when drinking extreme amounts in a short time, such as more than 1 liter per hour sustained. Symptoms include nausea, headache, and in severe cases, confusion or seizures. It's best to drink regularly throughout the day rather than large amounts at once.
How do I know if I'm well hydrated?
The simplest and most reliable indicator is the color of your urine. If it's pale yellow or nearly transparent, you're well hydrated. If it's dark yellow or amber, you need to drink more water. Other signs of dehydration include dry mouth, intense thirst, fatigue, dizziness, and infrequent urination (less than 4-6 times a day for an adult).
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