Calculators
BMI Calculator
BMI with context: your number, the WHO category it lands in, the healthy range for your height, and the distance to it — metric or imperial.
In short
Calculate BMI from height and weight in metric or imperial units, see your WHO category and healthy weight range, and how far you are from it. Free, private.
By NaveenKumar T · Updated
- Metric (cm/kg) & imperial (in/lb)
- WHO category at a glance
- Healthy weight range for height
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What BMI can and can't tell you
Body mass index endures because it needs only a scale and a tape measure, and at the population level it correlates with metabolic risk well enough to guide screening. The WHO adult bands this calculator reports are the global reference, and the healthy-range card inverts the formula — showing the weight window that maps to a 18.5–24.9 BMI at your exact height.
Its blind spots are equally well documented: identical BMIs can describe very different bodies, thresholds calibrate differently across ethnicities — several Asian guidelines use lower cutoffs — and it says nothing about where weight sits. Use the number as a starting point for a conversation — with yourself or a clinician — not as the conclusion.
WHO BMI categories
The four adult bands this calculator reports, plus two worked examples: at 170 cm and 68 kg, BMI is 23.53 — Normal weight — with a healthy range of 53.47–71.96 kg for that height. In imperial units, 5 ft 10 in (177.8 cm) and 160 lb (72.6 kg) gives BMI 22.96, also Normal weight, with a healthy range of 58.48–78.72 kg (128.9–173.6 lb) for that height. BMI is a screening measure, not a diagnosis: thresholds differ for children, athletes and some ethnic groups, so treat the category as a prompt to talk to a clinician, not a verdict.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Normal weight |
| 25–29.9 | Overweight |
| 30 and above | Obese |
| 23 or above (Asian populations, WHO 2004) | Increased risk |
| 27.5 or above (Asian populations, WHO 2004) | High risk |
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Frequently asked questions
Everything you need to know about the BMI Calculator.
01Is BMI different for Asian adults?
The categories this calculator shows are the WHO adult bands, which apply to all adults. A 2004 WHO expert consultation found that health risk rises at lower BMIs in Asian populations and proposed additional action points at 23 (increased risk) and 27.5 (high risk); the UK's NHS applies those lower thresholds to people of South Asian, Chinese, other Asian, Middle Eastern, Black African and African-Caribbean background. If that describes you, read a BMI of 23 or more the way the standard bands read 25.
02How is BMI calculated?
BMI = weight in kilograms ÷ height in metres squared. Imperial inputs are converted first (inches × 2.54, pounds × 0.4536). WHO adult ranges: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30+ obese — the category card maps your number onto them.
03How seriously should I take my BMI number?
As a screening signal, not a verdict. BMI ignores muscle mass, frame, age and distribution — athletes routinely read 'overweight' while lean. It's most useful tracked over time and confirmed with better measures (waist circumference, body-fat estimates) and a professional's judgment.
04What is a healthy weight for my height?
Invert the formula: healthy weight (kg) = BMI × height in metres squared, applied at the two band edges 18.5 and 24.9. At 175 cm (1.75 m), that is 18.5 × 1.75² to 24.9 × 1.75² = 56.7–76.3 kg. The healthy-range card runs this calculation for your exact height automatically, in either metric or imperial.