BMI Calculator (WHO & Asian Cut-offs)
Your BMI on WHO, Asian and Indian scales, with your healthy weight range.
Enter your weight and height.
Your BMI on each scale
| Cut-offs | Your category | Healthy weight |
|---|
Weight at key BMI values for your height
| BMI | Weight | What it marks |
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How it was calculated:
For general information only, not medical advice. Consult a qualified health professional for advice about your situation.
About the BMI Calculator (WHO & Asian Cut-offs)
Body mass index (BMI) is your weight in kilograms divided by the square of your height in metres. It is a quick screening number: it says how heavy you are for your height, not how much of that weight is fat.
This calculator shows your BMI on three adult scales side by side — the WHO international classification, the lower cut-offs that NICE recommends for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background (the same action points a WHO expert consultation proposed for Asian populations), and the Indian consensus cut-offs — plus the healthy weight range for your height, how far you are from it, BMI Prime and, if you add your waist, your waist-to-height ratio.
How to use it
- Choose kg · cm or lb · ft/in and enter your weight and height.
- Optionally add your age (adult categories apply from 20) and your waist for the waist-to-height ratio.
- Pick the cut-offs that fit your background — WHO, Asian/NICE or India 2009. The table below the result shows all three anyway.
- Read your BMI, category, healthy weight range and the change needed to reach it. Use Copy result or download the BMI table for your height.
Examples
BMI 22.9 · Healthy weight on all three scales · Healthy range 56.7–76.3 kg (WHO) or 56.7–70.1 kg (Asian) · BMI Prime 0.92
BMI 29.4 · WHO: overweight (pre-obese) · Asian/NICE: obesity class 1 · India 2009: obesity · 13.0 kg above the WHO range, 18.8 kg above the Asian range
BMI 24.2 · WHO: healthy weight · Asian/NICE and India: overweight · Waist-to-height ratio 0.52 (increased central adiposity)
How BMI is calculated
BMI = weight (kg) ÷ height (m)². For 70 kg and 1.75 m: 70 ÷ 1.75² = 70 ÷ 3.0625 = 22.9 — the worked example in WHO Technical Report 894.
In US units the same formula is BMI = 703 × weight (lb) ÷ height (in)²; this calculator converts pounds and inches exactly (1 lb = 0.45359237 kg, 1 in = 2.54 cm) and gives the same answer. BMI is shown to one decimal and the category is read from that rounded figure, so a BMI shown as 25.0 is never labelled "healthy".
BMI Prime is your BMI divided by 25, the WHO upper limit of the healthy range: below 1.00 means under that limit, 1.20 means 20% above it.
The healthy weight range is the weight at BMI 18.5 and at BMI 24.9 for your height (18.5–22.9 on the Asian cut-offs, 18.0–22.9 on the Indian ones).
WHO adult categories
- Underweight: below 18.5 — graded as mild thinness (17.0–18.4), moderate thinness (16.0–16.9) and severe thinness (below 16.0)
- Healthy weight (normal range): 18.5–24.9
- Overweight (pre-obese): 25.0–29.9
- Obese class I: 30.0–34.9 · class II: 35.0–39.9 · class III: 40 or more
The classes come from WHO Technical Report Series 894, Table 2.1, which notes that the same BMI can mean different amounts of body fat in different populations. The thinness grades are from WHO Technical Report Series 854. They are the same for men and women and do not change with age in adults.
Asian and Indian cut-offs
People of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background tend to carry more fat around the middle and develop type 2 diabetes and heart disease at a lower BMI. For them NICE guideline NG246 (recommendation 1.9.11) uses overweight 23–27.4 and obesity 27.5 or more, with obesity classes 2 and 3 starting 2.5 points lower than usual (32.5 and 37.5). These match the public-health action points of 23, 27.5, 32.5 and 37.5 proposed by the WHO expert consultation on BMI in Asian populations (Lancet, 2004), which also kept the standard WHO cut-offs for international comparison.
The 2009 Indian consensus statement (Misra et al., JAPI) defines normal 18.0–22.9, overweight 23.0–24.9 and obesity 25 or more for Asian Indians. A 2025 revision by the same group goes further: a BMI above 23 counts as obesity — stage 1 without effects on health or daily life, stage 2 when there is also excess waist size or waist-to-height ratio plus related symptoms or illness. Your doctor will decide which applies to you.
Waist-to-height ratio
Waist size says more about fat around the organs than BMI does. NICE asks adults with a BMI below 35 to keep their waist to less than half their height. To measure, find the bottom of your ribs and the top of your hips, wrap the tape midway between them (just above the belly button) and breathe out naturally. Divide waist by height in the same units: 96.5 cm ÷ 170 cm = 0.57.
- 0.4–0.49: healthy central adiposity
- 0.5–0.59: increased — increased health risks
- 0.6 or more: high — further increased health risks
These bands apply to men and women of all ethnicities, including muscular adults (NICE NG246, recommendations 1.9.5 and 1.9.14).
When BMI can mislead
- Muscular people and athletes can have a high BMI without excess fat — NICE advises interpreting BMI with caution in adults with high muscle mass. A body-fat estimate or waist-to-height ratio helps.
- People aged 65 and over: NICE advises interpreting BMI with caution, taking other health conditions and physical function into account, because a slightly higher BMI may be protective when older.
- Pregnancy: advice on weight gain in pregnancy is based on your BMI before pregnancy (the IOM 2009 guidelines), so use your pre-pregnancy weight here.
- Children and teenagers (2–19): BMI changes as children grow, so it is compared with children of the same age and sex as a percentile. Use the CDC Child and Teen BMI Calculator (ages 2–19); WHO uses its growth reference for ages 5–19.
Sources
- WHO, Obesity: preventing and managing the global epidemic, Technical Report Series 894 (2000), Table 2.1
- WHO, Physical status: the use and interpretation of anthropometry, Technical Report Series 854 (1995) — thinness grades
- WHO, Obesity and overweight fact sheet — adults: overweight ≥ 25, obesity ≥ 30
- WHO Expert Consultation, Appropriate body-mass index for Asian populations, Lancet 2004;363:157-63
- NICE, NG246 Overweight and obesity management, recommendations 1.9.10–1.9.15
- Misra A et al., Consensus statement for Asian Indians, JAPI 2009;57:163-70, and Revised definition of obesity in Asian Indians, Diabetes Metab Syndr 2025
Limitations
- BMI does not distinguish fat from muscle, bone or water, and it says nothing about where fat is stored.
- Adult categories do not apply to children and teenagers under 20, to pregnancy, or as a diagnosis of any condition — they are screening thresholds.
- The Asian and Indian cut-offs are guidance for groups, not exact limits for every person; a healthcare professional will interpret them with your other risk factors.
- Heights from 100 to 250 cm and weights from 10 to 500 kg are accepted.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
What is a healthy BMI?
On the WHO adult scale, 18.5 to 24.9. If your family background is South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean, NICE treats 23 and above as overweight, so the healthy range is 18.5 to 22.9. The Indian consensus uses 18.0 to 22.9.
Which cut-offs should I use if I am Indian?
The lower cut-offs. Both the Indian consensus (overweight from 23, obesity from 25) and NICE’s ethnicity-adjusted thresholds (overweight from 23, obesity from 27.5) start earlier than the WHO scale because Asian Indians have more body fat and higher diabetes risk at the same BMI. The calculator shows all three in the comparison table.
Is BMI accurate if I am very muscular?
Not on its own. Muscle is denser than fat, so strength athletes can have a BMI in the overweight range with little body fat. Add your waist to see the waist-to-height ratio, which NICE says can be used for adults with high muscle mass, or try the body fat calculator.
Can I use this for my child?
No. For ages 2 to 19, BMI has to be compared with other children of the same age and sex (BMI-for-age percentiles). If you enter an age under 20 the calculator still shows the number but not an adult category; use the CDC Child and Teen BMI Calculator.
What is BMI Prime?
Your BMI divided by 25, the upper limit of the WHO healthy range. A BMI Prime of 0.92 is 8% below that limit; 1.20 is 20% above it. It makes it easy to see how far you are from the limit without remembering the cut-off.
Why is my waist-to-height ratio not given a category?
NICE uses the waist-to-height ratio for adults with a BMI under 35. Above that, BMI already shows high risk, so the ratio is shown without a NICE band.