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 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.