Body Fat Calculator

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About this Calculator

Body Fat Ranges

Description	Women	Men
Recommended amount	20-25%	8-14%
Adults in United States, average	22-25%	15-19%
Obese	30+%	25+%

The American Council on Exercise Body Fat Categorization

Description	Women	Men
Essential fat	10-13%	2-5%
Athletes	14-20%	6-13%
Fitness	21-24%	14-17%
Average	25-31%	18-25%
Obese	32+%	25+%

Jackson & Pollard Ideal Body Fat Percentages

Age	Women	Men
20	17.7%	8.5%
25	18.4%	10.5%
30	19.3%	12.7%
35	21.5%	13.7%
40	22.2%	15.3%
45	22.9%	16.4%
50	25.2%	18.9%
55	26.3%	20.9%

Body Fat, Overweight, and Obesity

The scientific term for body fat is “adipose tissue.” Adipose tissue serves a number of important functions. Its primary purpose is to store lipids from which the body creates energy. In addition, it secretes a number of important hormones, and provides the body with some cushioning as well as insulation.¹

Body fat includes essential body fat and storage body fat. Essential body fat is a base level of fat that is found in most parts of the body. It is necessary fat that maintains life and reproductive functions. The amount of essential fat differs between men and women, and is typically around 2-5% in men, and 10-13% in women. The healthy range of body fat for men is typically defined as 8-19%, while the healthy range for women is 21-33%. While having excess body fat can have many detrimental effects on a person’s health, insufficient body fat can have negative health effects of its own, and maintaining a body fat percentage below, or even at the essential body fat percentage range is a topic that should be discussed with a medical professional.

Storage fat is fat that accumulates in adipose tissue, be it subcutaneous fat (deep under the dermis and wrapped around vital organs) or visceral fat (fat located inside the abdominal cavity, between organs), and references to body fat typically refer to this type of fat. While some storage fat is ideal, excess amounts of storage fat can have serious negative health implications.

Excess body fat leads to the condition of being overweight and eventually to obesity given that insufficient measures are taken to curb increasing body fat. Note that being overweight does not necessarily indicate an excess of body fat. A person’s body weight is comprised of multiple factors including (but not limited to) body fat, muscle, bone density, and water content. Thus, highly muscular people are often classified as overweight.

The rate at which body fat accumulates is different from person to person and is dependent on many factors including genetic factors as well as behavioral factors such as lack of exercise and excessive food intake. Due to varying factors, it can be more difficult for certain people to reduce body fat stored in the abdominal region. However, managing diet and exercise has been shown to reduce stored fat. Note that both women and men store body fat differently and that this can change over time. After the age of 40 (or after menopause in some cases for women), reduced sexual hormones can lead to excess body fat around the stomach in men, or around the buttocks and thighs of women.

Measuring Body Fat Percentage

U.S. Navy Method:

There are many specific techniques used for measuring body fat. The calculator above uses a method involving equations developed at the Naval Health Research Center by Hodgdon and Beckett in 1984. The method for measuring the relevant body parts as well as the specific equations used are provided below:

• Measure the circumference of the subject’s waist at a horizontal level around the navel for men, and at the level with the smallest width for women. Ensure that the subject does not pull their stomach inwards to obtain accurate measurements.
• Measure the circumference of the subject’s neck starting below the larynx, with the tape sloping downward to the front. The subject should avoid flaring their neck outwards.
• For women only: Measure the circumference of the subject’s hips at the largest horizontal measure.

Once these measurements are obtained, use the following formulas to calculate an estimate of body fat. Two equations are provided, one using the U.S. customary system (USC) which uses inches, and the other using the International System of Units, specifically the unit of centimeters:

Body fat percentage (BFP) formula for males:

USC Units:

BFP = 86.010×log10(abdomen-neck) – 70.041×log10(height) + 36.76

SI, Metric Units:

BFP =4951.0324 – 0.19077×log10(waist-neck) ) + 0.15456×log10(height)- 450

Body fat percentage (BFP) formula for females:

USC Units:

BFP = 163.205×log10(waist+hip-neck) – 97.684×(log10(height)) + 36.76

SI, Metric Units:

BFP =4951.29579 – 0.35004×log10(waist+hip-neck) + 0.22100×log10(height)- 450

Note that results of these calculations are only an estimate since they are based on many different assumptions to make them as applicable to as many people as possible. For more accurate measurements of body fat, the use of instruments such as bioelectric impedance analysis or hydrostatic density testing is necessary.

Fat mass (FM) formula:

FM = BF × Weight

Lean Mass (LM) formula:

LM = Weight – FM