Water Intake Calculator
How much water you should drink each day
Water Intake Chart by Body Weight
Daily water = weight × 0.033 litres; one glass is 250 ml (8.5 oz). Drink more when exercising, in hot weather or during pregnancy. Tap a row to load that weight into the calculator.
Free Daily Water Intake Calculator
Know how much water to drink for your body weight
Water keeps almost every system in your body working, from temperature control and digestion to skin and kidney health. A simple way to estimate your daily need is to multiply your body weight in kilograms by 0.033, which gives your target in litres. Enter your weight and this calculator shows that amount in litres and the equivalent number of glasses. Remember that hot weather, exercise, illness and pregnancy all increase how much you need, so treat this as a baseline and drink more when you sweat.
Features
Based on Your Weight
Uses the widely cited weight × 0.033 litre formula.
Litres & Glasses
See your target in both litres and 250 ml glasses.
A Smart Baseline
A solid starting point to adjust for activity and climate.
Private & Free
No sign-up and nothing leaves your device.
Water by Body Weight & What Raises Needs
Daily water by weight (≈ 33 ml/kg)
- 50 kg → ~1.7 litres
- 60 kg → ~2.0 litres
- 70 kg → ~2.3 litres
- 80 kg → ~2.6 litres
- 90 kg → ~3.0 litres
What raises your needs
- Exercise: +500-1,000 ml per hour
- Hot and humid weather
- Pregnancy and breastfeeding
- Fever, vomiting or diarrhoea
Frequently Asked Questions
How is daily water intake calculated?
A common formula multiplies your body weight in kilograms by 0.033 to get your daily need in litres. For example, a 70 kg person needs about 2.3 litres.
Is there a water intake chart by weight?
Yes — the chart under the calculator lists the daily target for 40–120 kg (88–265 lb) in litres and glasses, using the same weight × 0.033 formula. Tap a row to load that weight, then add more on training days and in hot weather.
Does this include water from food?
Food, especially fruit and vegetables, provides some fluid too. The figure here is a general target for total intake, so you don't need to drink every drop as plain water.
Should I drink more when I exercise?
Yes. Sweating increases fluid loss, so drink extra before, during and after exercise, and in hot or humid weather.
Can I drink too much water?
Very rarely, drinking excessive amounts in a short time can be harmful. Spread your intake through the day and drink to thirst rather than forcing large volumes at once.
Is the 8-glasses-a-day rule true?
Eight glasses (~2 litres) is a handy generalisation; real needs vary with weight, activity and climate. A weight-based estimate is a more personal starting point.
Do tea and coffee count towards my intake?
Largely yes — caffeinated drinks count as fluid. Still, getting most of your daily fluid from plain water is the healthiest habit.