BMI calculator
Enter your height and weight in metric or imperial units to get your body mass index, the WHO category it falls into and the weight range considered healthy for your height.
Result
- Your BMI
- 24.3
- Category (WHO)
Normal weight
- Healthy weight range (BMI 18.5–24.9)
- 121.7–163.8 lb
How to use this tool
- Choose metric (cm and kg) or imperial (inches and pounds).
- Enter your height. For imperial, convert feet to inches: 5 ft 8 in is 68 in.
- Enter your weight. Your BMI, category and healthy weight range appear instantly.
Good to know
- Categories follow the WHO adult classification; the healthy range covers BMI 18.5 to 24.9.
- BMI is a screening measure for adults and does not account for muscle mass, age, sex or pregnancy.
Frequently asked questions
How is BMI calculated?
Body mass index is your weight in kilograms divided by your height in metres squared. In imperial units the same result comes from weight in pounds multiplied by 703 and divided by height in inches squared. A person 170 cm tall weighing 65 kg has a BMI of 65 ÷ 1.7² = 22.5.
What do the BMI categories mean?
This page uses the World Health Organization bands for adults: below 18.5 is underweight, 18.5 to 24.9 is the normal range, 25 to 29.9 is overweight and 30 or above is obese. The category is based on the BMI rounded to one decimal, so 24.95 is shown as 25.0 and classed as overweight.
How is the healthy weight range worked out?
The range multiplies the lower and upper normal BMI values, 18.5 and 24.9, by your height in metres squared, or in imperial units by height in inches squared divided by 703. At 68 inches that gives roughly 122 to 164 pounds. It is a population guideline, not a personal target.
Is BMI accurate for everyone?
No. BMI does not separate muscle from fat, so athletes can read as overweight while people with little muscle can read as normal despite excess fat. It is not designed for children, pregnant women or older adults with muscle loss, and many Asian countries use lower cut-offs for overweight and obesity.
Why do other sites give a different healthy weight?
Most differences come from the cut-offs used. Many Asian countries, including Korea, treat a BMI of 23 or more as overweight, which lowers the top of the healthy range. Rounding the height, using stones, or adding waist-based measures also shifts the numbers by a few pounds or kilograms.
Results are estimates for general information. Double-check anything important with an official source.