Water Intake Calculator
Estimate how much water you should drink each day from your weight. Works in metric or imperial units.
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How much water should you drink?
Water makes up about 60% of your body weight and is essential for temperature regulation, nutrient transport and waste removal.
A common guideline is 30–40 ml per kg of body weight per day, adjusted for weather, exercise and health.
How we calculate it
We estimate 30–40 ml per kg of body weight, with a recommendation of 35 ml/kg:
| Item | Calculation |
|---|---|
| Daily water | weight (kg) × 30–40 ml |
Keep in mind
This is a baseline reference. You may need more when:
- It is hot or you are sweating a lot
- You exercise (especially long or intense sessions)
- You are pregnant or breastfeeding
- You have fever, diarrhea or other fluid loss
Frequently asked questions
How much water should I drink a day?
A general guideline is 30–40 ml per kg of body weight. This calculator gives a recommendation and range from your weight — drink more in heat or during exercise.
Does coffee and tea count as water?
Yes. Most beverages count toward your daily fluid intake, though sugary drinks and alcohol should not be your main source.
Can I drink too much water?
Rarely, but drinking a very large amount in a short time can cause low blood sodium. Drink to thirst and need — no need to force excess.
How do I know if I am hydrated?
A simple check is urine colour: pale yellow usually means well hydrated, dark yellow suggests you need more fluids.
Does this calculator store my data?
No. All calculations run locally in your browser and nothing is uploaded or saved.