Enter the skinfold measurements (mm) of the biceps, triceps, subscapular, and iliac into the calculator to determine the body density.

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## Body Density Formula

The following formula is used to calculate a body density.

D= 1.1422 – [.0544*log (skinfold sum (mm) ) ]

- Where D is the body density (g/m^3)
- skinfold sum = skinfold of biceps + triceps + subscapular + iliac

This equation is used for males age 30-39. The following table displays the formula how males and females of different ages. In the formula below, log(s)= log(skinfold sum of the 4 measurements)

Age | Men | Women |

< 17 | D = 1.1533 – (0.0643 * log(s)) | D = 1.1369 – (0.0598 * log(s)) |

17-19 | D = 1.1620 – (0.0630 * log(s)) | D = 1.1549 – (0.0678 * log(s)) |

20-29 | D = 1.1631 – (0.0632 * log(s)) | D = 1.1599 – (0.0717 * log(s)) |

30-39 | D = 1.1422 – (0.0544 * log(s)) | D = 1.1423 – (0.0632 * log(s)) |

40 -49 | D = 1.1620 – (0.0700 * log(s)) | D = 1.1333 – (0.0612 * log(s)) |

> 50 | D = 1.1715 – (0.0779 * log(s)) | D = 1.1339 – (0.0645 * log(s)) |

## Body Density Definition

**What is a body density? **A body density is defined as the total mass per unit volume of an individual human. It’s often estimated using a formula like the one above, which takes skinfold measurements throughout the body.

## Example Problem

How to calculate body density?

**First, take the measurements of the skinfold in each of the 4 areas.**For this example, we find measurements as follows: 2mm, 3mm, 5mm, 2mm, for the biceps, triceps, subscapular, and iliac respectively.

**Next, sum the skinfold measurements.**Adding the measurements together we get a sum of 12mm.

**Finally, calculate the body density.**Calculate the body density using the formula above. D = 1.1422 – ( .0544 * log ( 12) ) = 1.083 g/cm^3.

## About Body Density

**How can body density be used to calculate body fat %? **Using the Siri equation, a body fat percentage can be calculated using body density. This equation states bodyfat% = (457-body density) -414.

**What are skinfolds? **Skinfolds are specific locations on the body that skin is pulled and measured to determine the body fat percentage of an individual.