Calculate your personalised daily water intake based on weight, activity level, and climate. Results in litres, fluid ounces, and equivalent glasses.
Open Water Intake Calculator → free, no sign-inHydration recommendations vary by body weight and activity level — the generic '8 glasses a day' doesn't account for individual differences. The Water Intake Calculator gives a personalised recommendation based on your weight, activity level, and climate, expressed in litres, fluid ounces, and equivalent glasses.
Athletes managing hydration during training, health-conscious individuals tracking daily intake, or anyone who wants a personalised hydration target rather than a generic guideline.
No tutorials. No learning curve. Open it and get started.
No server uploads. Results in litres, fluid ounces, and equivalent glasses — whichever unit you track with.
Completely free. No trial period. No premium tier for basic functionality. No account required. Use it as often as you need.
One job, done well. Water Intake Calculator was built to solve a specific problem cleanly. No feature bloat, no ads, no distractions.
Is 8 glasses a day accurate for everyone?
No — hydration needs vary by body weight, activity, and climate. Personalised calculation is more accurate.
Does coffee count towards water intake?
Caffeinated drinks are mildly diuretic but still contribute net hydration. Count them at about 70% of their volume.
Do I need more water when exercising?
Yes — add approximately 0.5L per hour of moderate exercise.
Does hot weather increase needs?
Yes — sweating increases water loss significantly in hot climates.
Is it possible to drink too much water?
Yes — hyponatremia (water intoxication) is possible with excessive intake. The recommendations here are within normal healthy ranges.
Free. Instant. No sign-in. Open it and get the job done.
Open Water Intake Calculator on Doathingy.com →