About daily water intake
This water intake calculator estimates how much water to drink each day based on your body weight and how much you exercise, and shows the result in litres, millilitres, cups and ounces. Hydration needs vary with climate, activity and health, so treat it as a helpful starting point. It runs in your browser.
How Water Intake works
How to use it
- Enter your weight (kg or lb).
- Enter how many minutes you exercise per day.
- Read your suggested daily water in several units.
The guideline
A common rule of thumb is about 30–35 ml of water per kilogram of body weight, with extra added for exercise (roughly 350 ml per 30 minutes). The tool combines both.
Listen to your body
Needs rise in hot weather, at altitude, during illness, and in pregnancy or breastfeeding. Thirst and pale-yellow urine are good everyday signs you are well hydrated.
Common uses
- Estimate daily water needs
- Plan hydration around exercise
- Convert water to cups, ml or ounces
- Set a daily drinking goal
- Stay hydrated in hot weather
- Support a fitness routine
- Build a healthy habit
- Get a quick hydration reference
Frequently asked questions
How much water should I drink a day?
Around 30–35 ml per kg of body weight plus extra for exercise — this tool estimates it for you.
Does exercise increase my needs?
Yes — add roughly 350 ml for every 30 minutes of activity, more in heat.
Do other drinks count?
Water from tea, coffee, milk and food all contribute, but plain water is the easiest to track.
Can I drink too much water?
Very rarely, but excessive intake in a short time can be harmful — spread it through the day.
Does the unit matter?
No — the tool shows litres, ml, cups and ounces.
Is my data uploaded?
No — it calculates in your browser.
Is this medical advice?
No — it is a general guide; ask a professional about specific needs.
Is it free?
Yes — completely free with no sign-up.