The Body Fat Percentage calculator computes body fat percentage based on the individual's BMI, age and gender.
INSTRUCTIONS: Choose units and enter the following:
- (BMI) Body Mass Index
- (AGE) Person's Age
- (SEX) Person's Gender
Body Fat Percentage (BF%): The body fat index is returned as a percent.
The Math / Science
The Body Fat Percentage is a measure of fitness level, since it is the only body measurement which directly calculates a person's relative body composition without regard to height or weight. It is the total mass of fat divided by total body mass; body fat includes essential body fat and storage body fat. Essential body fat is necessary to maintain life and reproductive functions. The percentage of body fat for women is greater than for men, due to the demands of childbearing and other hormonal functions.
The following formula is used for adults :
`BF%=(1.20*BMI)+(0.23*AGE)-(10.8*SEX)-5.4`.
For children this formula is used:
`BF%=(1.51*BMI)-(0.70*AGE)-(3.6*SEX)+1.4`, where:
- `BMI` = body mass index
- `AGE` = age
- `SEX` = sex
The following table shows average percentages for men and women.
| Description | Women | Men |
| Essential fat | 10-13% | 2-5% |
| Athletes | 14-20% | 6-13% |
| Fitness | 21-24% | 14-17% |
| Average | 25-31% | 18-24% |
| Obese | 32%+ | 25%+ |
Additional Resources -
Check out the Heart Heath Calculator and the Metabolic Health Calculator for more Health and Fitness Equations.
References -
WIkipedia (https://en.wikipedia.org/wiki/Body_fat_percentage)
