Water Intake Calculator
Enter your body weight, how much you exercise, and whether you're in a hot climate, to get an estimated daily water intake recommendation.
How the Water Intake formula works
A common weight-based baseline, with adjustments:
Base intake (L) = weight(kg) × 0.033 + 0.35 L per 30 minutes of exercise + 0.5 L in hot/humid climates
Step-by-step calculation
- Multiply your body weight in kilograms by 0.033 to get a baseline daily water target in liters.
- Add roughly 0.35 liters for every 30 minutes of exercise, to account for fluid lost through sweat.
- Add another 0.5 liters if you're in a hot or humid climate.
Worked example
A 70 kg person who exercises 45 minutes a day in a normal climate: Base = 70 × 0.033 = 2.31 L. Exercise addition ≈ 0.53 L (for 45 minutes). Total ≈ 2.84 L per day.
Frequently asked questions
Does this include water from food and other beverages?
This estimate is for total fluid intake broadly, though roughly 20% of daily water intake typically comes from food in a normal diet — so treat this as a general target rather than requiring that exact amount from plain water alone.
Is more water always better?
No — needs vary by individual, and drinking far beyond what your body needs doesn't provide extra benefit and, in rare extreme cases, can be harmful. This calculator gives a reasonable general estimate, not a personalized medical recommendation.