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Your health,
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Free health calculators to help you understand your body. BMI, calories, water intake, sleep, heart rate and more — simple tools for everyone.

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Find your Body Mass Index using height and weight in UK units.

Calorie calculator

Work out your daily calorie needs and macro split (TDEE).

Water intake calculator

Find out how much water you should drink each day.

Sleep cycle calculator

Find the best time to wake up and feel fully rested.

Heart rate zone calculator

Calculate your training zones based on your age and max heart rate.

Alcohol unit checker

Count your weekly alcohol units and compare to UK guidelines.

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What does your BMI actually mean?

How many calories do you really need each day?

How much water should you drink every day?

Safe & private

All calculations happen in your browser. We never store your data.

Science-backed

Formulas based on established research and clinical guidelines.

Mobile friendly

Works perfectly on any device — phone, tablet or desktop.

UK-first

Stones, pounds, pints and NHS guidelines built in by default.