Skip to main content
toolcool
Health

BMI Calculator · Body Mass Index with Healthy Weight Range

Instantly compute your Body Mass Index (BMI) from height and weight, switch between metric/imperial, compare WHO international vs Chinese (WS/T 428) Asian-population categories and see your healthy weight range. Runs entirely in your browser.

Overview

BMI (Body Mass Index) is the most widely used weight-category indicator globally — weight (kg) divided by height (m) squared. This tool supports both metric (cm, kg) and imperial (in, lb) inputs, and shows side-by-side WHO international vs Chinese WS/T 428-2013 Asian-population categories. The two differ slightly on the overweight/obese thresholds because Asian bodies typically carry more visceral fat per unit BMI. Your height-matched healthy weight range is also shown. For reference only; consult a physician for a full assessment.

How to use

  1. Pick unit system (metric cm + kg, or imperial in + lb).
  2. Pick standard (WHO international or Chinese Asian-population).
  3. Enter height and weight. Results show BMI, your category, healthy weight range, and the two standards side by side.

Formula

1) BMI = weight(kg) / height(m)²
2) Imperial: 1 inch = 2.54 cm, 1 lb = 0.45359237 kg
3) Standards (underweight / normal / overweight / obese):
   WHO: <18.5 / 18.5–24.9 / 25–29.9 / ≥30
   China WS/T 428-2013: <18.5 / 18.5–23.9 / 24–27.9 / ≥28
4) Healthy weight = 18.5·h² … 24.9·h² (WHO) or …23.9·h² (Asian)

Common scenarios

Scenario 1 · 170 cm / 65 kg

BMI ≈ 22.5, normal under both WHO and Asian standards.

Scenario 2 · 175 cm / 78 kg

BMI ≈ 25.5, borderline overweight by WHO but mid-overweight by Asian standard — a typical region where the two diverge.

Scenario 3 · 170 cm / 50 kg

BMI ≈ 17.3, underweight in both. Focus on balanced nutrition and muscle gain rather than pure weight gain.

FAQ

Is lower BMI always healthier?

No. BMI under 18.5 correlates with weaker immunity, reduced bone density, hormonal issues. Aim for the normal range with a healthy muscle/fat ratio, not the lowest possible BMI.

Does BMI apply to athletes?

Limited. Muscular athletes often show "overweight" BMI with very low body fat. Use body-fat % and waist-hip ratio as complementary indicators.

Why is the Asian standard stricter?

Asians (especially East Asians) carry more visceral fat and show higher metabolic risk at the same BMI. WHO's 2002 Asia-Pacific guidance lowered overweight to 23; China's WS/T 428-2013 uses 24/28 based on local epidemiology.

Does this apply to children?

No. Children need age- and sex-specific BMI percentile charts, not adult thresholds. This tool is for adults; use WHO child growth standards or see a pediatrician.

Does this tool upload my data?

No. Everything runs locally in your browser; nothing is uploaded.

Should pregnant women use this?

Not recommended. Pregnancy weight gain follows its own guidelines based on pre-pregnancy BMI. Consult your obstetrician.

Related tools