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Daily Water Intake Calculator
Most adults need roughly 30–35 ml of water per kilogram of body weight per day, plus extra for exercise and heat. This calculator turns that general guide into a daily range for your weight and activity. Enter your details below to get your guide.
What is the Water Intake Calculator?
The Water Intake Calculator is a free tool that estimates your daily water needs. It uses your weight and activity level. It gives a guide in litres, not a strict target. Thirst and urine color are better daily signals than any formula.
How to use this tool
- Enter your weight.
- Choose your activity level.
- Select Show my water guide to see your daily guide.
- Read your range in litres and cups.
General daily water guide
Includes water from food and other drinks. Spread intake through the day — do not force it all at once.
No sign-up needed — the tool works right here in your browser.
How to actually hit it
- Start the day with a glass — while you sleep, you lose fluid through breathing and sweat.
- Keep water visible — a bottle on your desk beats willpower.
- Drink with meals — it is the easiest habit anchor there is.
- Check the color test: pale straw urine usually means you are hydrated; dark yellow means drink more. Clear-as-water every time can mean you are overdoing it.
- Exercise days: drink during and after training, and replace what you sweated out — do not wait until you are very thirsty.
Turn hydration into a daily habit
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See plans & free trial →Frequently asked questions
How much water should I drink per day?
A common general guide is roughly 30–35 ml per kilogram of body weight per day, plus extra for exercise and heat. For a 70 kg adult, that is about 2.1–2.5 litres. Needs vary widely with climate, activity, health conditions, and medication.
Can you drink too much water?
Yes. Drinking far more water than your body needs can dilute blood sodium (hyponatremia), which is dangerous. Do not force extreme volumes — spread intake through the day and let thirst and urine color guide you.
Does coffee or tea count as water?
Mostly yes. Coffee, tea, and other unsweetened drinks hydrate you, and food provides roughly a fifth of daily water. Alcohol does not count — it increases fluid loss.
Do I need to sign up to use this water calculator?
No. The tool works right here in your browser — no account, no name or email needed.
Disclaimer: General guide, not a prescription. Needs vary with climate, activity, health conditions, and medication — follow your clinician's advice if you have kidney or heart conditions, or if you take medication that affects fluid balance.