BMI Calculator
Calculate body mass index from height and weight in metric or imperial units, and see the adult category of the World Health Organization.
BMI Calculator
Adults only. Not medical advice.
- BMI (kg/m²)
- 22.9
- WHO adult category
- Normal weight
- Normal range at this height (kg)
- 56.7 to 76.3
Quick facts
- Price
- Free
- Sign-up
- Not required
- Where it runs
- On your device
- Files uploaded
- No
- Limits
- No fixed limit
- Updated
BMI Calculator works out body mass index from height and weight, in metric or imperial units, and names the adult category of the World Health Organization. It is for adults only, it is not medical advice, and BMI ignores muscle and body build. Use it to get a quick number for a form or a conversation, and to see the weight range that counts as normal at your height.
How to use
- Choose Metric or Imperial under Units.
- Type your height: centimetres for metric, or feet and inches for imperial. An empty inches box counts as 0.
- Type your weight in kilograms or in pounds.
- Read the BMI, the WHO adult category and the Normal range at this height, which is the weight that gives a BMI from 18.5 to 24.9.
- If a box is empty, not a number or out of range, a message under it says what to fix.
Examples
A person 175 cm tall who weighs 70 kg has a BMI of 22.9, which is Normal weight. At 175 cm the normal range runs from 56.7 to 76.3 kg.
In imperial units, 5 ft 9 in and 154 lb give a BMI of 22.7, also Normal weight. Notice that the category follows the number as shown, rounded to one decimal, so a BMI that shows as 25.0 is Overweight even if the exact value was 24.96.
Limits
The categories are the cut-offs of the World Health Organization for adults: below 18.5 is underweight, 18.5 to 24.9 is normal weight, 25.0 to 29.9 is overweight (pre-obesity), and 30.0 or more is obesity. They do not apply to children, teenagers or pregnant women. Heights must be from 50 to 300 cm and weights from 10 to 650 kg, or the same in feet, inches and pounds. BMI does not measure fat, muscle, age or health.
FAQ
How is BMI calculated?
BMI is your weight in kilograms divided by your height in metres, squared. For imperial units the tool first converts exactly, using 2.54 centimetres to the inch and 0.45359237 kilograms to the pound, then applies the same formula.
Is BMI a good measure of health?
It is only a screening number. Because it ignores muscle, bone, fat distribution and age, two people with the same BMI can have very different health. This tool gives no medical advice, so speak to a doctor about your own situation.
Can I use it for my child?
No. These categories are for adults. Children and teenagers are assessed against growth charts for their age and sex, which this tool does not have.
Is my height and weight stored or sent?
No. The calculation happens in this page on your device, and nothing you type is uploaded or kept.