BMI Calculator
Body mass index compares your weight to your height. Enter yours to see your BMI, your WHO category, and the healthy weight range for your height.
How to use this calculator
- Choose metric or imperial units — whatever your scale and tape show.
- Enter your height and weight; no other inputs needed.
- Read your BMI, category, and the weight range that keeps you between BMI 18.5 and 24.9.
How BMI is calculated
BMI = weight (kg) ÷ height² (m²)A person who weighs 70 kg at 1.75 m has a BMI of 70 ÷ (1.75 × 1.75) = 22.9 — comfortably in the healthy band. The WHO classifies adult BMI as follows:
| BMI | WHO category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity class I |
| 35.0 – 39.9 | Obesity class II |
| 40 and above | Obesity class III |
Frequently asked questions
Is BMI accurate for muscular people?
Not really — it only sees total mass. Someone heavy from muscle can read “overweight” at low body fat. If you train seriously, pair BMI with the body-fat calculator or a waist measurement.
What is a healthy BMI for Asian adults?
Risk of type-2 diabetes and cardiovascular disease tends to rise at lower BMIs in Asian populations. WHO expert consultation suggests screening cut-offs of 23 (increased risk) and 27.5 (high risk) for many Asian groups.
Does BMI apply to children and teenagers?
No — ages 2–19 are assessed with age- and sex-specific percentile charts, not the adult cut-offs used here.
How often should I check my BMI?
It only matters as a trend. Checking monthly alongside your weight trend is plenty; daily fluctuations are mostly water.