Body fat percentage is a crucial metric in assessing overall health and fitness. There are various methods available for estimating body fat, each with its own strengths and limitations. One such method is the Navy Hodgdon-Beckett method, commonly known as the Navy Body Fat Formula. Developed by the U.S. Navy, this method provides a practical and reliable way to estimate body fat percentage, especially for military personnel.

Important Note: The Navy Body fat formula is often confused with the Navy Hodgdon Weight-Height Regression Body fat formula which is also available.

**17.46%**

**Body Fat**(Athletes)

> 32.0 Obese

25.0-32.0 Average

21.0-25.0 Fitness

14.0-21.0 Athletes

< 14.0 Essential fat

## The Navy Body Fat Formula

The Navy Body Fat Formula is based on a simple linear regression model that takes into account the relationship between body circumference measurements and body fat percentage. The formula requires three measurements:

- for Males - height, neck circumference, and abdomen circumference
- for Females - height, neck circumference, waist circumference and hip circumference

The formula utilizes logarithmic functions to estimate the body fat percentage from these measurements. First it creates an output called density which will then get converted to Body Fat percentage.

Side note: There are a couple of variations of this formula "floating around" the internet but all with the same result. The original papers sourced below are contain references referring to the formulas with their density variables. Other calculators may combine this into a single formula with slightly different constants.

This Body Fat formula is slightly better suited for more active individuals and provides a better estimate for Body fat.

Based On | Weight | Tape Measure | Skinfold |

Measurement Complexity | Very Easy | Easy | Difficult |

Accuracy/Precision | Low | Medium | High |

Best Suited For | Non-Active Person | Active Enthusiast | Athlete |

## Understanding the Results

Healthy Ranges: Body fat percentage varies based on factors such as age and gender. For men, a body fat percentage between 6-24% is considered normal, while for women, the normal range is between 16-30%.

Interpretation: A higher body fat percentage may indicate a higher risk of obesity-related health issues, while too low a percentage may pose health risks as well.

## Considerations and Limitations

- Population-Specific: The Navy Body Fat Formula was initially developed for military personnel and might not be as accurate for the general population.
- Alternative Methods: While the Navy method is convenient, there are other accurate methods like Dual-Energy X-ray Absorptiometry (DEXA) and hydrostatic weighing. These methods might be more precise but can be less practical due to cost and accessibility.
- Individual Variation: Body fat distribution varies among individuals, and this formula might not capture those differences accurately.

## Conclusion

The Navy Hodgdon-Beckett Weight-Height Regression method offers a straightforward and accessible way to estimate body fat percentage. While it may not be as precise as some advanced techniques, it provides a useful tool for individuals looking to monitor their body composition. As with any method, it's essential to understand its limitations and consider consulting with a healthcare professional for a comprehensive assessment of your health and fitness.

### Measurement Help

#### Neck

**How to measure**

- Smallest measurement just below the adams apple
- Tape measure should be sloping slightly downwards

#### Waist

**Body Position**

- breathe out to "remove slack"
- You may want to flex your ab muscles to help on finding a neutral mid section position

**How to measure**

- Narrowest part of your mid section below rib cage and above top of the hip bone
- Generally at or above the naval area, its possible that this location may "move" as you change body composition

#### Hip

**Body Position**

- Standing on flat surface with feet slightly appart (generally right below your respective hip joint)

**How to measure**

- largest measurement generally in the middle of your hip, ie the peak of your butt

https://apps.dtic.mil/sti/citations/ADA143890

https://apps.dtic.mil/sti/citations/ADA146456

https://apps.dtic.mil/sti/citations/ADA306887