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Health & Fitness Calculators

Water Intake Estimator

A rough daily drinking target based on body weight, adjusted for exercise and hot weather. Thirst, urine colour and your doctor’s advice should always take priority.

Suggested daily water2.7 L90 US fl oz

Glasses (250 ml): 11
From body weight: 2,310 ml
For exercise: 350 ml

Step-by-step working

Base: 70 kg × 33 ml = 2,310 ml
Exercise: 350 ml per 30 minutes = 350 ml
Temperate climate: no adjustment
Total ≈ 2.66 L

This is drinking water; about 20% of daily water also comes from food. People with heart, kidney or liver conditions, or who are pregnant or breastfeeding, should follow medical advice.

How to use the Water Intake Estimator

Enter your weight.
Enter your typical daily exercise and climate.
Press Calculate.

Formula

Daily water ≈ 33 ml × body weight (kg) + 350 ml per 30 minutes of exercise + 500 ml in hot weather.

For comparison, the European Food Safety Authority’s adequate total water intake (from drinks and food) is 2.5 L a day for men and 2.0 L for women.

Examples

70 kg, 30 minutes of exercise: 2,310 + 350 = ≈ 2.7 L (about 11 glasses).

Frequently asked questions

Can I drink too much water?

Yes. Drinking very large amounts in a short time can dilute blood sodium (hyponatraemia). Spread intake over the day.

Do tea and coffee count?

Yes, most drinks contribute to hydration, including tea and coffee in moderate amounts.