CalculynHow it works
A common rule of thumb is half an ounce of water per pound of body weight, plus about 12 oz for every 30 minutes of exercise. Food also provides some of your daily water. Needs rise in hot weather.
Formula
Water (oz) = weight (lb) × 0.5 + 12 × (exercise minutes ÷ 30)
Example
A 170 lb person who exercises 30 minutes a day needs about 97 oz (2.9 L).
Assumptions & limitations
- Based on population formulas that may not fit athletes, pregnancy, children or medical conditions.
Frequently asked questions
Does coffee count?
Yes, most beverages contribute to hydration, including coffee and tea in moderate amounts.