How to calculate body fat

Not all people have the same ideal body fat percentage. It varies with age, sex and genetics. An adult might be better at a higher or lower body fat than another adult in the same age and sex. And the desirable body fat of athletes can vary depending on the sport (swimmers seem to perform better at a higher body fat percentage than runners).

When losing fat, it is important to know not just how much weight you are losing, but how much of your body is muscle and how much is fat. You want to lose fat while maintaining or even building muscle. So, you need some way to keep track of your body fat percentage.

Calculate Body Fat

You can learn how to measure your body, and how to calculate your body fat percentage here:

Calculating your body fat at home

Use a tape measure to determine your waist circumference at the smallest point, your wrist, your hips at the widest point, and your forearm (unflexed):

Measure your Waist Measure your Waist

To get an accurate measurement of your waist, you need first to remove any layers or clothing blocking your waist.

Now, use your fingers to find the top of your hips, and the base of your ribs. Your waist is the soft section between these two bony parts.

Make sure the measuring tape is parallel to the floor and also ensure that the tape measure is snug to your body but not so tight that it compresses the skin.

Exhale while measuring and relax your abdomen.

Measure your Wrist Measure your Wrist

Use a flexible, soft tape measure to measure your wrist around the widest point.

Wrap the tape measure around your wrist as if it were a bracelet or watch.

To get a better and accurate measurement you can do this 2-3 times and calculate your average.

Measure your Hips Measure your Hips

Find a mirror to help you ensure the tape is not twisted or uneven. Now you can remove your clothes to obtain an accurate measurement.

Measure the circumference of your hips. Start at one hip and wrap the tape measure around your rear, around the other hip, and back to where you started.

Make sure the tape is over the largest part of your buttocks.

Look in the mirror to see if the measuring tape is parallel to the floor and make sure is not twisted.

Relax your muscles without losing your posture and exhale. Do not pull the tape measure tightly.

Measure your Forearm Measure your forearm

You can need another person to do the measuring for you.

The forearm should be measured at the largest area (2 inches below the elbow), where the brachioradialis peks, making this the largest circumference of the forearm

The best time to measure your body is in the morning. Your body weight and waist measurements are the most accurate after you wake up from 8 hours of sleep.

How to calculate body fat for women

For example, to calculate body fat for a woman that weighs 126, has a wrist measurement of 6.0, a waist measurement of 23, a hip measurement of 37, and a forearm measurement of 9.

Figure #1 = (Weight x 0.732) + 8.987

Example: (126 x 0.732) + 8.987 = 101.219

Figure #2 = Wrist / 3.14

Example: 6 / 3.14 = 1.91

Figure #3 = Waist x 0.157

Example: 23 x 0.157 = 3.611

Figure #4 = Hip x 0.249

Example: 37 x 0.249 = 9.213

Figure #5 = Forearm x 0.434

Example: 9 x 0.434 = 3.906

Lean Body Mass = Figure 1 + Figure 2 - Figure 3 - Figure 4 + Figure 5

  • Example: 101.219 + 1.91 - 3.611 - 9.213 + 3.906 = 94.211

Body Fat weight = Weight - Lean Body Mass

  • Example: 126 - 94.211 = 31.789

Body Fat Percentage = (Body Fat Weight x 100) / Total bodyweight

  • Example: (31.789 x 100) / 126 = 25.22%

How to calculate body fat for men

For example, to calculate body fat for a man that weighs 190, and has a waist measurement of 30.5

Figure #1 = (Weight x 1.082) + 94.42

Example: (190 x 1.082) + 94.42 = 300

Figure #2 = Waist x 4.15

Example: 30.5 x 4.15 = 126.575

Lean Body Mass = Figure #1 - Figure #2

  • Example: 300 - 126.575 = 173.425

Body Fat Weight = Weight - Lean Body Mass

  • Example: 190 - 173.425 = 16.575

Body Fat Percentage = (Body Fat Weight x 100) / Weight

  • Example: (16.575 x 100) / 190 = 8.72%

Calculate your body automatically

You can determine now your body fat percentage with our body fat calculator. Use a tape measure to determine your waist, wrist, hips and forearm. Then input your height, weight and gender to receive a body fat index based on average values;