BMI Calculator: Estimate Body Mass Index from Height and Weight
A BMI calculator divides weight by height squared to give a screening estimate. Enter consistent metric values and use the result as general information rather than a diagnosis.
Calculate body mass index
- Enter your weight and choose kilograms or pounds.
- Enter your height and choose centimetres, inches, feet or feet and inches.
- Select Calculate BMI to see the estimate and the weight and height the tool used.
- Check that the numbers and units are right.
- Talk to a qualified professional about your health, because BMI is only a screening estimate.
BMI formula and interpretation
BMI is calculated as weight in kilograms divided by height in meters squared. A number alone does not measure body composition, fitness, nutrition status or overall health.
Who should not rely on this estimate
Adult BMI ranges may not be appropriate for children, pregnancy, some athletes, older adults or individual clinical assessment. This tool does not diagnose a condition or recommend treatment.
Units
Enter your weight and choose kilograms or pounds, then enter your height and choose centimetres, inches, feet or feet and inches. With feet and inches an extra box appears for the inches. The tool converts everything and shows the kilograms and centimetres it used, so you can check the numbers. The result is the BMI to one decimal place.
Reading the result
A person who weighs 70 kg and is 175 cm tall has a BMI of 22.9, and a person of 154 pounds who is 5 feet 10 inches tall has a BMI of about 22.1. The usual adult ranges are under 18.5 for underweight, 18.5 to 24.9 for normal weight, 25 to 29.9 for overweight and 30 or more for obesity. Some health bodies use lower limits for people of South Asian origin, so ask a doctor which ranges apply to you.
What BMI cannot tell you
BMI does not separate muscle from fat, so a strong athlete can have a high BMI, and it does not show where fat is carried or how healthy your habits are. It is not used in the same way for children, who are judged on growth charts, or during pregnancy. Treat the number as a screening estimate and talk to a doctor or a dietitian about your own health.
Frequently asked questions
How do I calculate BMI with feet and inches?
Choose Feet and inches, enter the feet and the inches, then your weight in kg or pounds. The tool converts to centimetres and kilograms and shows the BMI. The formula is weight in kg divided by height in metres squared.
What is a normal BMI for adults?
The usual adult ranges are under 18.5 underweight, 18.5 to 24.9 normal weight, 25 to 29.9 overweight and 30 or more obesity. BMI is a screening estimate, not a diagnosis, so ask a doctor about your health.
Is BMI a medical diagnosis?
No. It is a screening estimate and cannot determine a person’s health on its own.
Why should I confirm the units?
Entering pounds as kilograms or centimeters as meters changes the result substantially. Use the labels shown by the calculator.
How do I calculate BMI with pounds and feet?
Choose Pounds for weight and Feet and inches for height, then type the numbers. The tool converts them.
Is a high BMI always unhealthy?
No. It is a screening estimate and does not measure fat or fitness.
Is the result a diagnosis?
No. Only a doctor can assess your health.
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