Water Intake Calculator
Weight and training in — liters, cups, and glasses out.
How this is calculated
liters = (kg × 35 + exercise-minutes ⁄ 30 × 350) ÷ 1000
Worked example: 70 kg with 60 minutes of training → 2,450 + 700 = 3.15 liters — about 13 cups. That total includes fluid from food, coffee, and tea; it is a day-shaped guideline, not a jug to down at once. Heat, altitude, and long sweaty sessions push needs above the formula — thirst and pale-yellow urine are the live gauges. Not medical advice.
Frequently asked questions
How much water should I drink a day?
A practical guideline is about 35 ml per kilogram of body weight, plus roughly 350 ml for every 30 minutes of exercise — that is what this calculator computes. For a 70 kg person with an hour of training, about 3.15 liters, including water from food and other drinks.
Does coffee or tea count toward it?
Yes — the mild diuretic effect of normal caffeine intake does not cancel the fluid. Food counts too (roughly 20% of typical intake). The target here is total fluid, not glasses of plain water only.
Should I drink more in heat?
Yes — heat and altitude raise needs beyond the formula, sometimes by a liter or more on hot active days. Thirst plus pale-yellow urine is the practical gauge the formula cannot replace.
Can I drink too much?
Yes — drinking many liters in a short window can dilute blood sodium (hyponatremia), which is dangerous. Spread intake across the day and add electrolytes for very long sweaty sessions. As with everything on this page: a guideline, not medical advice.