BMI Calculator

Body Mass Index

The Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. There are two formulas for calculating BMI:
  • BMI = weight in kg / (height in m)2
  • BMI = weight in kg / height in cm / height in cm × 10,000
  • (These formulas give the same answer.)

You can calculate your BMI with this BMI calculator:

BMI Calculator

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imperial

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metric

imperial

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The limits of this calculator are set to:
  • The world's tallest man (8ft 11in).
  • The world's smallest man (21in).
  • The world's heaviest man (92st 10lb).
  • The world's lightest man (1st 1lb).

Examples of BMI Calculation

Here is an example using the first formula:
  • BMI = weight in kg / (height in m)2
John is 93 kg and 1.78m tall.

BMI = 93 / 1.782

BMI = 93 / 3.168

BMI = 29.4

Here is the same example using the second formula:
  • BMI = weight in kg / height in cm / height in cm × 10,000

BMI = 93 / 178 / 178 × 10,000

BMI = 0.0029352 × 10,000

BMI = 29.4

BMI is usually rounded to one decimal place.

Metric or Imperial?

This calculator converts the imperial measurements to metric with the following before applying the formula:
  • 1 inch = 2.54 cm
  • 2.2 lbs = 1 kg
  • 1 foot = 12 inches
  • 1 stone = 14 pounds

For example, Simon weighs 11 stone 3lbs and is 5'4" tall.

Simon's weight in pounds = (11 x 14) + 3

Simon's weight in pounds = 157 pounds

Simon's weight in kg = 157 / 2.2

Simon's weight in kg = 71.36 kg

Simon's height in inches = (5 x 12) + 4

Simon's height in inches = 64 inches

Simon's weight in cm = 64 × 2.54

Simon's weight in cm = 162.56 cm

Simon's weight in m = 1.63 m (rounded to 2 decimal places)