How much water should I drink per day?

General guidance is 2 litres (8 glasses) per day for adults. However, your actual needs depend on your weight (35ml per kg body weight is a common formula), activity level, and climate.

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health

Water Intake Calculator

Find out exactly how much water you should drink daily based on your weight, activity level, and climate.

Water Intake CalculatorFree · No signup

Weight (kg)

Activity Level

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About This Calculator

Our Water Intake Calculator is designed specifically for UK businesses and individuals. All calculations use current 2025/26 rates and follow UK guidelines.

This tool is completely free to use with no signup required. You can use it as many times as you like. The results are instant and calculated in your browser — no data is sent to our servers.

Also known as

water intake calculatorhow much water should I drinkdaily water intake calculatorhydration calculatorwater calculator

Frequently Asked Questions

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Last updated: 1 April 2026 · Rates for 2025/26 tax year