MultiKit

BMI Calculator: Body Mass Index With WHO and Asian Cut-offs

  • Free
  • No sign-up
  • Runs in your browser
  • Version 1.0.1
  • Last updated 2026-10-25
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Enter your weight and height to get your body mass index, the class it falls in, and the weight range that counts as normal for your height. Choose metric or US units, and the international WHO classes or the lower Asia-Pacific ones used in Korea.

BMI is a screening number, not a diagnosis. It does not tell muscle from fat, so it can mislead for athletes, older adults and people who are pregnant, and the classes are for adults aged 18 and over. For children and teenagers use the growth charts of a doctor. Talk to a doctor or dietitian about your weight.

Everything you enter is processed in your browser and is never sent to a server.

How to use

  1. Choose Metric (kg, cm) or US (lb, ft, in), then enter your weight and height.
  2. Choose the classes: WHO is the international standard; Asia-Pacific / Korea puts overweight at 23 and obesity at 25, because health risks begin at lower BMI in Asian populations.
  3. Read the BMI, its class and where it sits on the bar. Below it is the weight range that is in the normal class for your height, and how far you are from it.
  4. Read the notes under the result: BMI is a rough screening figure.

Examples

70 kg, 175 cm
→ BMI 22.9, normal weight; normal range for 175 cm is 56.7 to 76.3 kg
BMI is weight in kilograms divided by height in meters squared: 70 ÷ 1.75² = 22.86.
154 lb, 5 ft 9 in
→ BMI 22.7, normal weight
The same person in US units; it is converted to 69.9 kg and 175.3 cm first.
75 kg, 180 cm, Asia-Pacific classes
→ BMI 23.1, overweight (at risk); WHO classes call the same figure normal
The two scales differ between 23 and 25.

How it works

The page divides your weight in kilograms by your height in meters squared. Pounds, feet and inches are first converted with exact definitions (1 lb is 0.45359237 kg, 1 inch is 2.54 cm). The class is the one whose lower limit is the highest that is not above your BMI, by the cut-offs of the scale you chose. The normal range for your height is the BMI of 18.5 up to just under the next limit (24.9 on the WHO scale, 22.9 on the Asia-Pacific one) times height squared.

The page reports figures and does not diagnose. It does not change the classes for age or sex, which the adult cut-offs do not do either. The calculation and the conversion are covered by tests, and the page is checked in a real browser.

Sources

Frequently asked questions

What is BMI?
Body mass index is weight in kilograms divided by the square of height in meters. It is a quick way to compare weight for height across people, and a screening step, not a measure of body fat or of health.
What are the classes?
By the WHO: under 18.5 underweight, 18.5 to 24.9 normal, 25 to 29.9 overweight, 30 to 34.9 obese class 1, 35 to 39.9 class 2, 40 and over class 3. For Asian populations the WHO's 2004 expert group and the Korean obesity guideline use 23 to 24.9 as overweight at risk, 25 to 29.9 as obese class 1, and 30 and over as class 2 (35 and over class 3).
Why can BMI be wrong for me?
It cannot tell muscle from fat or say where fat is carried. A muscular person can have a high BMI with little fat, and an older person can have a normal BMI with little muscle. It is also meant for adults of 18 or more, not for children or teenagers, and it is not used during pregnancy.
Should I try to reach the normal range?
That is a question for a doctor, who can look at waist size, blood tests, family history and your own history. The page only shows where the figure sits.
Is anything sent to a server?
No. The figures stay in your browser.
Version history
  • 1.0.1 — Clarifies the search title with the tool's main task and whether it is free or runs online.
  • 1.0.0 — First release.

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