Online Tool Store
Water Intake Calculator
Estimate your daily water intake target based on body weight, activity level, and climate, shown in milliliters, ounces, or cups. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example shown - replace with your own numbers.
Daily target
Roughly per hour (16h awake)
General hydration guidance, not medical advice - individual needs vary.
How the water intake calculator works
- Enter your body weight, activity level, and climate.
- The tool starts from a baseline of about 33 mL per kilogram of body weight.
- It adds extra fluid for activity level and multiplies by a climate factor for warm or hot conditions.
The formula
daily target (mL) = (weight (kg) × 33 + activity mL) × climate factor
FAQ
Where does the base 33 mL per kg come from?
It is a commonly cited general hydration baseline (roughly 30-35 mL per kg of body weight) used by many nutrition guides as a starting point for healthy adults.
Does this account for exercise?
Yes. Choosing a higher activity level adds extra fluid on top of the base amount, reflecting water lost through sweat during exercise.
Is this medical advice?
No. This is general hydration guidance, not medical advice. People with kidney, heart, or other conditions affecting fluid balance should follow guidance from their doctor instead.
Does food count toward this total?
This estimate is for fluid intake specifically. In practice, food (especially fruits and vegetables) also contributes meaningfully to daily hydration.
How we compare
| Feature | Online Tool Store | Generic "8 glasses a day" rule | Hydration tracking apps |
|---|---|---|---|
| Personalized to your weight | ✓ | ✗ | ✓ |
| Adjusts for activity and climate | ✓ | ✗ | Varies |
| No app install or account | ✓ | ✓ | ✗ |
For a quick, personalized target without downloading a tracking app, Water Intake Calculator gets you a number to aim for.