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BMI calculator
Your body mass index, its category and the healthy weight range for your height. Change a number and the answer moves with it.
Healthy range for your height: 56.7 kg to 76.6 kg
95% of the healthy limit
WHO standardWhat does this mean?WHO is the World Health Organization. Its cut-offs, overweight from 25 and obese from 30, are the standard almost everywhere and what most doctors in Europe and the Americas use.
Your BMI stays the same. Only the lines between the categories move.
A screening number, not a diagnosis. Talk to a doctor about anything that worries you.
BMI categories for adults
| Category | BMI (WHO) | BMI (Asian cut-offs) |
|---|---|---|
| Underweight | < 18.5 | < 18.5 |
| Healthy | 18.5 to 24.9 | 18.5 to 22.9 |
| Overweight | 25 to 29.9 | 23 to 24.9 |
| Obese | 30 to 34.9 | 25 to 29.9 |
| Severely obese | 35+ | 30+ |
About this number
BMI compares weight to height. It does not measure fat, so it misreads athletes, pregnancy and older adults.
Two standards decide where each category starts:
WHO standardCurrent
Underweight under 18.5, healthy 18.5 to 24.9, overweight from 25 and obese from 30. Used almost everywhere. Japan keeps these numbers but calls 25 or more obese.
Asian standard
Healthy 18.5 to 22.9, overweight from 23 and obese from 25. WHO experts proposed it because Asian populations carry more health risk at the same BMI. Korea uses it.
BMI=Weight÷ (Height×Height)
Weight in kilograms, height in metres. Other units are converted first.
Sources
- Obesity and overweight
World Health Organization, 2025
- Adult BMI categories
CDC, 2024
- Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies
WHO Expert Consultation, The Lancet, 2004
Questions people ask
How is BMI calculated?
BMI is your weight in kilograms divided by your height in metres squared. In pounds and inches it is 703 times your weight divided by your height in inches squared. At 72 kg and 1.75 m that is 72 / (1.75 x 1.75) = 23.5.
What is a healthy BMI?
For adults, 18.5 to 24.9 by the World Health Organization's categories. Korea uses the lower Asia-Pacific cut-offs, overweight from 23 and obese from 25, because the same BMI carries more metabolic risk in Asian populations, and Japan calls a BMI of 25 or more obese.
Does BMI depend on age or sex?
Not for adults. The number uses only weight and height, and the adult categories are the same for men and women at every age from 20. Under 20, age and sex do matter: use the child BMI calculator.
What is the difference between BMI and body fat percentage?
BMI compares your weight with your height; body fat percentage is the share of your weight that is fat. Two people with the same BMI can carry very different amounts of fat, so for the fat itself, the body fat calculator estimates it from a tape measure.
Is BMI accurate?
It is a screening number. It does not tell muscle from fat, so it reads high on muscular people and can read normal on someone with little muscle and a lot of fat. The waist to height ratio adds what BMI misses.
Does BMI work for children?
Not with the adult categories. A child's BMI is read as a percentile for age and sex; use the child BMI calculator.
Every calculator, free
Eight ways to read the same measurements. No account, nothing saved anywhere but your browser.
- Body fat calculatorUS Navy method, from three tape measurements
- Ideal weight calculatorFour formulas, and the BMI range
- BMR calculatorThe calories your body burns at complete rest
- TDEE calculatorYour daily calories, and the macros that fit them
- Waist to height ratio calculatorWaist to height, and waist to hip
- Child BMI calculatorPercentile for age and sex, children and teens 2 to 19
- Kg to lbs to stone, and cm to feet and inchesKilograms, pounds, stones, centimetres, feet and inches
Bemivo for iPhone and Android
Keep every number, and see where it is going.
The Bemivo app is a weight tracker: a trend line that ignores the daily noise of the scale, goals with a projected date, and the whole family in one account. It starts with a free trial.
- History and a trend line that ignores daily noise
- Goals with a projected date
- Home Screen widgets, and Lock Screen on iPhone
- Weigh-in reminders
- Up to 10 profiles for the family
- Body measurements, CSV and a PDF for your doctor
The calculators on this website stay free.