BMI Calculator
Work out your Body Mass Index from height and weight, in metric or imperial — with your category and a healthy-weight range. Free and private.
Report a problemBMI is a general guide for adults — it doesn’t account for muscle, build, age, pregnancy or ethnicity, so it isn’t medical advice. Speak to a health professional about your weight.
How to use
- Choose metric (kilograms and centimetres) or imperial (pounds, feet and inches) at the top.
- Type your weight and height. Your BMI, your category and a healthy-weight range update live as you type — there is nothing to submit.
- Read the result: the big number is your BMI, the marker shows where you fall on the scale, and the range is the weight that would put you in the healthy band for your height.
FAQ
How is BMI calculated?
BMI is your weight divided by your height squared. In metric that is kilograms ÷ (metres × metres). In imperial it is 703 × pounds ÷ (inches × inches). The adult categories are: under 18.5 is underweight, 18.5 to 24.9 is the healthy range, 25 to 29.9 is overweight, and 30 or more is obese. This tool does both unit systems for you and also shows the weight range that would put you in the healthy band for your height.
Is anything I type sent to a server?
No. Your height and weight are used for plain arithmetic right in your browser — nothing is uploaded or stored. The calculator works offline and keeps your numbers private.
Is BMI accurate for everyone?
BMI is a quick, useful guide for most adults, but it is only a rough screen. It can read high for very muscular people and low for older people with less muscle, and it is not meant for children, pregnancy or athletes. Treat it as a starting point, not a diagnosis, and talk to a health professional for advice about your own health.