BMI Calculator

Body mass index, weight category and your healthy weight range.

cm
kg
22.9Your BMI
Normal weightCategory
Healthy weight for your height
56.7 kg – 76.3 kg
To reach the healthy range
You are within the healthy range.
BMI prime (ratio to 25)
0.91
WHO BMI categories for adults
BMICategory
Below 18.5Underweight
18.5 – 24.9Normal weight
25.0 – 29.9Overweight
30.0 – 34.9Obesity class I
35.0 – 39.9Obesity class II
40.0 and aboveObesity class III

BMI is a screening measure, not a medical diagnosis. Consult a healthcare professional for personal advice.

About the BMI Calculator

Body mass index (BMI) is a simple screening number that relates your weight to your height: BMI = weight (kg) ÷ height (m)². Health organisations such as the WHO use it to group adults into underweight, normal, overweight and obesity categories, because on a population level higher BMI correlates with higher risk of heart disease, type 2 diabetes and other conditions.

This calculator accepts metric or imperial units, shows your category, and also tells you the weight range that corresponds to a "normal" BMI for your height, together with how much you would need to gain or lose to reach it.

BMI has real limitations. It does not distinguish muscle from fat, so athletes can score "overweight" while being lean, and it does not account for age, sex, ethnicity or where fat is stored. Treat it as one indicator among many, not a diagnosis.

How to use the BMI Calculator

  1. Choose metric or imperial units.
  2. Enter your height and weight. Results update instantly.
  3. Read your BMI, category and the healthy weight range for your height.

Frequently asked questions

What is a healthy BMI?

For adults, a BMI between 18.5 and 24.9 is classified as normal weight by the World Health Organization. Below 18.5 is underweight; 25 to 29.9 is overweight; 30 and above is obesity.

Is BMI accurate for athletes or older adults?

Not always. Muscle weighs more than fat, so muscular people can have a high BMI with little body fat. Older adults may have a "normal" BMI but low muscle mass. Waist circumference and body-fat measurements give a fuller picture.

Does BMI apply to children?

Children and teens use age- and sex-specific BMI percentiles rather than the fixed adult cut-offs. This calculator is intended for adults aged 20 and over.

How is BMI calculated in pounds and inches?

BMI = 703 × weight (lb) ÷ height (in)². For example, 160 lb at 5 ft 10 in (70 in) gives 703 × 160 ÷ 4,900 ≈ 23.0.