Body & Weight

BMI Calculator

Enter your height and weight to find your Body Mass Index (BMI), see which World Health Organization category it falls into, and learn the healthy weight range for your height.

Calculate your BMI

kg
cm
Your BMI23.5Normal weight
1540
  • Underweight
  • Normal weight
  • Overweight
  • Obese
Healthy weight for your height
57 kg – 76 kg

BMI is a screening tool — it does not distinguish muscle from fat. Very muscular people may read high.

This is an educational estimate, not medical advice. Consult a qualified professional.

Save & share your result

How the BMI calculator works

Body Mass Index is a simple ratio of weight to height. The formula is BMI = weight (kg) ÷ height (m)². If you use imperial units, this tool converts your pounds and feet/inches to metric first, so the result is identical either way.

BMI was developed in the 19th century by Adolphe Quetelet and is used worldwide as a quick, low-cost screen for weight-related health risk across large populations. Because it needs only two measurements you almost certainly already know, it remains the most widely cited starting point for a weight assessment.

Reading your BMI category

The World Health Organization groups adult BMI into four broad bands. The coloured gauge above shows where your value sits:

  • Under 18.5 — underweight, which can signal undernutrition or other health issues.
  • 18.5 to 24.9 — a healthy weight for most adults.
  • 25 to 29.9 — overweight, where risk of conditions such as type 2 diabetes begins to climb.
  • 30 and above — obese, linked to substantially higher risk of cardiovascular and metabolic disease.

The limits of BMI

BMI measures mass, not body composition, so it cannot tell muscle from fat. A muscular athlete may register as "overweight" while carrying very little fat, and an older adult with low muscle mass may sit in the healthy range yet carry excess fat. BMI also does not account for where fat is stored — and abdominal fat carries more risk than fat on the hips or thighs.

For a fuller picture, pair your BMI with a body-fat estimate and a waist-based measure such as waist-to-height ratio. Thresholds also differ for some populations: many health bodies use a lower overweight cut-off (around 23) for people of South Asian descent. Treat BMI as a useful first flag, not a diagnosis, and discuss any concerns with a healthcare professional.

Track your progress at home

As an affiliate we may earn from qualifying purchases — at no extra cost to you.

Frequently asked questions

What is a healthy BMI?

For most adults, a BMI between 18.5 and 24.9 is considered healthy. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese, according to the World Health Organization.

Is BMI accurate for athletes?

Not always. BMI counts muscle and fat the same way, so very muscular people can be classed as overweight despite low body fat. Athletes should also look at body-fat percentage and waist measures.

Does BMI work the same for men and women?

The BMI formula and adult categories are the same for men and women. Body composition differs between sexes, which is one reason BMI is best used alongside other measures.

Is BMI used for children?

Children and teens use age- and sex-specific BMI percentiles instead of the fixed adult categories. This adult calculator is intended for people aged 18 and over.

Embed this calculator

Free to use on your own website, blog, or article — just copy the snippet below. It loads the live calculator and includes a small link back to HealthyLifeStyles.

Sources & references

  1. World Health Organization. "Obesity and overweight" fact sheet (BMI classification and health risks).