Water Intake Calculator
Staying hydrated is essential for health, energy, and performance. Our water intake calculator uses your body weight as the base (35 ml per kg), then adjusts for your activity level and whether you live in a hot climate. The result shows your daily target in liters, 250 ml glasses, and 8 oz cups.
Frequently Asked Questions
How much water should I drink per day?
A common guideline is 35 ml per kilogram of body weight for a sedentary person in a temperate climate. Active people and those in hot weather need significantly more. For a 70 kg person with moderate activity, this is typically around 2.5–3 liters per day.
Does coffee and tea count toward daily water intake?
Yes — all beverages including coffee, tea, juices, and even food moisture count toward your daily fluid intake. However, alcohol has a diuretic effect and should not be counted.
What are signs of dehydration?
Common signs include dark yellow urine, dry mouth, fatigue, dizziness, and headaches. Mild dehydration (1–2% of body weight) can already impair physical and cognitive performance.
Should I drink more when exercising?
Yes. During intense exercise you can lose 0.5–2 liters of fluid per hour through sweat. Drink 400–600 ml before exercise and replace fluids regularly during and after your workout. The activity level selector in this calculator already accounts for this.