# How to Calculate Your Body Mass & Fat Percentage

Written by frank kermes
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An effective weight loss programme requires concrete goals. In order to set such goals, it is helpful to determine your exact body mass composition and your body fat percentage. You can calculate how much of your body mass is fat by using simple skinfold calipers to test the thickness of skinfolds at three sites around your body.

Skill level:
Moderate

### Things you need

• Skinfold calipers
• Metric tape measure
• Calculator
• Marking pen

## Marking Skinfold Sites for a Male

1. 1

Mark the chest test site. The chest site should be a diagonal fold halfway between your armpit and nipple.

2. 2

Mark the abdomen test site. The abdomen site should be a vertical fold 2 cm to the right of your navel.

3. 3

Mark the thigh test site. The thigh site should be a vertical fold between your hip and knee joints.

## Marking Skinfold Sites for a Female

1. 1

Mark the triceps test site. The triceps site should be a vertical fold on the back of your arm, in between the top of your shoulder and your elbow.

2. 2

Mark the suprailiac test site. The suprailiac site should be a diagonal fold just above the crest of your pelvis.

3. 3

Mark the thigh test site. The thigh site should be on the front of your thigh, between your knee and hip joints.

## Measuring the Skinfold Sites

1. 1

Grasp the skinfold with thumb and forefingers approximately 1 cm to either side of the mark.

2. 2

Gently close the calipers on the site as near to the thumb and fingers as possible.

3. 3

Release the calipers and hold for approximately two seconds after they stop moving inwards.

4. 4

Take at least two measurements from each site. Record the average measurement of each site in millimetres.

## Calculating your Body Fat Percentage

1. 1

Calculate your body density by taking the sum of your three site measurements in millimetres through this equation: Body Density = (1.1093800 - (0.0008267 X (Sum of three measures)) + (0.0000016 X (3 measures X 3 measures)) - (0.0002574 X Age)

2. 2

Calculate your body fat percentage with the following formula: Body fat percentage = (((4.95 / Body Density) - 4.50) X 100)

3. 3

To determine your lean body mass, subtract your percentage of body fat from 100. That is the percentage of your lean body mass.

#### Tips and warnings

• For best results, measure when the skin is dry and no lotion has been applied. Measure before exercising, as exercise can change the hydration content of the skin and produce inaccurate results. Measure all sites on the right side of your body.

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