Free Water Intake Calculator - How Much Water Should You Drink?
Find out exactly how much water you should drink daily based on body weight and activity level.
Formula & Methodology
The Hydration Goals Calculator estimates your daily water need from body weight — about 33 ml per kilogram as a baseline — then adds 350 ml for every 30 minutes of exercise you log. The result is a personalised daily target rather than the generic eight-glasses rule.
- Base Water (ml) = Body Weight (kg) × 33
- Total Need = Base Water + (Exercise Minutes / 30) × 350 ml
Worked Example
Using the Hydration Goals Calculator: apply the formula above to your input values. For instance, Base Water (ml) = Body Weight (kg) × 33, then Total Need = Base Water + (Exercise Minutes / 30) × 350 ml. The tool performs each step instantly and shows the result.
Frequently Asked Questions
How much water should I drink daily?
It estimates a target from your body weight and activity, often landing near 2-3 litres, adjusted for exercise and climate.
Does exercise increase my water needs?
Yes. You lose fluid through sweat, so active days and hot weather raise how much you should drink.
Do other drinks and foods count?
Yes. Water-rich foods and most beverages contribute to hydration, though plain water remains the most efficient source.