Free Online BMI Calculator
Use this free BMI calculator to work out your body mass index from your height and weight. It supports metric and imperial units, including centimetres, metres, feet, inches, kilograms, pounds, stones, and stones with pounds.
The tool is useful for anyone who wants a quick BMI estimate without converting units manually. Choose your preferred height and weight format, enter your details, then click calculate. The calculator will show your BMI score and a general category. BMI can be a handy starting point, but it is only a rough guide and does not measure muscle, fitness, body shape or overall health.
How To Use This BMI Calculator
Select your height and weight units, enter your details and click Calculate. The calculator converts your values and works out your BMI automatically.
About BMI
BMI is a simple height-to-weight calculation. It can be useful as a rough guide, but it does not measure muscle, fitness, body shape or overall health. Basically, it thinks a rugby player and a sofa goblin can be the same thing. Helpful, but limited.
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BMI Calculator FAQ
What units can I use?
You can enter height in centimetres, metres, or feet and inches. Weight can be entered in kilograms, pounds, stones, or stones and pounds.
Is BMI always accurate?
No. BMI is only a general guide. It does not account for muscle mass, body composition, age, fitness level or medical history.
What does my BMI category mean?
The category gives a rough indication based on your BMI number, such as underweight, healthy weight, overweight or obese. It should not replace medical advice.