BMI is the world’s most used measure of human body fat. It compares weight to height.

Where does BMI come from? Who invented it?

The concept and formula for BMI evolved over several decades before being finalised by the American scientist Ancel Keys in 1972.

Yes, because at a mass population level, it is an accurate predictor of premature death caused by excess body weight.

How is BMI Calculated?

BMI is calculated by a mathematical formula which divides weight by height. The most convenient way to calculate yours is to use the free calculator on this page.

Is BMI always right for Everyone?

BMI is not as useful or relevant for pregnant women and growing children. It is also less useful for the elderly and unusually tall or short people. People with comparatively long or short torsos or limbs may be mischaracterized by common BMI readings.

What are the BMI Categories?

The eight main categories of BMI are: Very Severely Underweight, Severely Underweight, Underweight, Normal, Overweight, Obese Class 1, Obese Class 2, and Obese Class 3.

Does BMI measure Body Fat?

No, BMI does not measure body fat directly, but it is a reliable indicator of body fat across a population of people. A simple mathematical formula comparing weight with height is not sufficient to determine body fat accurately.

Is BMI recognised by everyone?

Since BMI is officially recognised by the World health Organisation, it is the most widely recognised and used measure of healthy body weight in the world.

Is BMI used by Doctors?

Yes, all doctors use BMI as a basic reference to general healthy body weight. More specific and accurate measurements are often used following an initial consultation.

Yes, insurance professionals use BMI when calculating health and mortality probabilities. It is a basic input for life and health insurance calculations.

Do different types of Body Frames affect BMI?

Yes, individual body frame sizes and shapes affect BMI and its usefulness as a health indicator. People with unusually large body frames, and those with unusually small frames generate disproportionately larger and smaller BMI results. Thus, their true body fat percentage may be lower or higher than would be expected in more average body framed people.

Does Muscle Mass affect BMI?

Yes, and for this reason people with unusually small or large quantities of muscle mass should not rely on their BMI result as an indicator of healthy weight. An example of the latter are bodybuilders, who tend to register overweight BMI despite having comparatively low levels of body fat.

Does Gender matter for BMI?

Whilst gender does make a difference with BMI results, the normal convention is to use the same category delineations for men and women. Even though biological factors determine that women have a proportionately (+30%) higher body fat percentage than men, both are grouped in the same categories for the sake of practical efficacy.

Does Ethnicity matter for BMI?

Like gender, ethnicity does affect BMI results, but the same universal BMI categories and ranges are officially used for all ethnicities. Read the section “Sometimes BMI gets it Wrong!” to learn more.

Is BMI an Accurate measure of Healthy Weight?

For most people, yes. BMI is the easiest, most convenient, and only universally accepted indicator of healthy weight in a population, so for these reasons alone it is an accurate measure of healthy weight. However, there are many situations at the individual level wherein BMI could be highly inaccurate.

Does BMI say How much Weight to Lose or Gain for better Health?

Yes, since the main objective of BMI is to define a healthy range of body weights for any given height, BMI “tells” the individual exactly how much weight to lose or gain to reach a statistically optimum weight. Please read the “Sometimes BMI gets it Wrong” to learn about limitations and exceptions.

Is BMI the only (or best) Way to measure Healthy Weight?

BMI is not the only, and certainly not the best, way for a person to find out if their weight is healthy. However, it is the easiest and most recognised way to do so. Other measures like the Waist to Hip Ratio or the Body Fat Percentage measure can provide better metrics at the individual level.

BMI Calculator · calcount

Use this accurate BMI Calculator to find out what your Body Mass Index (BMI) is. Simply move the sliding scale or type in your current weight (kg) and height (cm) to see your calculated Body Mass Index. The BMI Calculator will display your BMI and BMI Classification below the sliders:

BMI Calculator for both Women and Men

This metric BMI Calculator is suitable for both women and men. We do not recommend its use for children. It is best to use this tool in combination with your waist measurement. Read on further to learn why Body Mass Index is such a popular method for defining what a healthy weight range is.

Body Mass Index classifies the body weights of different people, relative to a perceived good health ideal. It is probably the best framework to use in order to measure the relative healthy weight for most people.

Use our calcount Calorie Calculator to find out how many calories you need to change your BMI. Better yet, why not register a free calcount Calorie Tracker account to take full control of your body weight goals?