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Sprawdź ile wody potrzebujesz dziennie uwzględniając wagę, aktywność i klimat.
Computes exact water needs based on body weight, activity level and climate.
The basic rule is 35 ml × kg of body weight. A 70 kg person should drink about 2.45 l per day. Requirements increase significantly with exercise and high temperatures.
| Activity | Extra water |
|---|---|
| 1h workout | +0.5–0.7 l |
| Hot climate | +0.5–1.0 l |
| Pregnancy | +0.3 l |
Dark urine, fatigue, headache and difficulty concentrating are the first signs. Dehydration of just 2% of body weight reduces physical performance by 10–20% and impairs cognitive function.
Do coffee and tea count? Yes — caffeinated drinks have a mild diuretic effect but still provide net hydration.
When to drink? Start your day with 2 glasses of water. Drink regularly throughout the day — don't wait for thirst, which appears when you're already dehydrated. Also check the food guide.
Even mild dehydration of 1–2% of body weight can impair cognitive performance, mood and physical endurance. The commonly cited "8 glasses a day" is a simplification — your actual needs depend on weight, activity, climate and diet. This calculator uses ~35 ml per kg of body weight as a baseline, adjusted for activity.
| Urine colour | Hydration status |
|---|---|
| Pale yellow (lemonade) | ✅ Well hydrated |
| Dark yellow | ⚠️ Drink more water |
| Amber / brown | ❌ Dehydrated |