DylRicho: Dylan Richards

Calculate your body mass index value.

Important Information

This calculator has been specifically designed with the World Health Organization's (WHO) recommendations on body mass index value interpretation and the accompanying scale.

Other specific calculators exist for , , and where different interpretations and scales are recommended. For all other ethnical regions, you should use this calculator.

The body mass index value is always calculated using kilograms (kg) and meters (m), but you can choose your own units of measurement here and the calculator will automatically convert them.

in; kg
cm; kg
in; lb

Enter your height in your chosen unit.

Enter your weight in your chosen unit.

The result will be displayed below, with the answer given in kilograms per square meter (kg/m²).

The indicator below will change position depending on the calculated body mass index value.

0

The body mass index value can be interpreted as follows:

  • 15.9 and below — severely underweight;
  • 16.0 – 16.9 — underweight;
  • 17.0 – 18.4 — moderately underweight;
  • 18.5 – 24.9 — healthy weight;
  • 25.0 – 29.9 — overweight;
  • 30.0 – 34.9 — obese (class I; moderately obese);
  • 35.0 – 39.9 — obese (class II; obese);
  • 40.0 and above — obese (class III; severely obese).

Important Information Regarding the Limitations of the Body Mass Index (BMI) Value

The body mass index (BMI) value is a reasonable indicator of overall body health, but it must be understood that it's merely one datapoint, and the human body is an incredibly complex structure.

Here are just some of the limitations of the body mass index value:

  • As muscle tissue is approximately 15% more dense than fatty tissue, the body mass index formula will produce higher values for individuals with higher-than-average muscle mass;
  • The uses an exponent of 2, which doesn't align with the square-cube law of scaling three-dimensional objects. The new body mass index formula, used by this calculator, aims to address this pitfall with an exponent of 3, but may still be somewhat inaccurate as the human body grows disproportionately more vertically versus laterally throughout childhood;
  • Due to the aforementioned limitations of accurate scaling, this formula is also highly likely to overestimate (give a higher than desired value) for taller frames, and underestimate (give a lower than desired value) for shorter frames;
  • Individuals receiving treatment for an eating disorder shouldn't use this value as a meaningful datapoint;
  • This value historically hasn't been a good indicator for an increased risk in potentially life-threatening conditions, such as heart attack or stroke, or indeed death itself.

By no means should this value be solely relied upon, and treated as a substitute for seeking professional medical advice. If you're concerned about your health, seek advice from medically trained professionals.

Revisions made to this tool will be documented below, organized by date in descending order.

Thursday, September 15, 2022

  • Initial release.