How to Calculate Body Fat Measurements

Calculate body fat using one of the measurements below. Refer to the body fat chart in the tips section to see what your level of health is for the amount of body fat that you have and what might be a target value for you after you calculate your amount of body fat.

Instructions

• 1

  Estimate the weight of your body fat. Start with 50 kilograms and add 2.3 kilograms for each inch over 5 feet for ideal body weight (IBW) in males. Use the alternative equation if you are a female by substituting 45.5 kilograms into the equation instead of the 50 kilograms used for males. Convert the IBW result from this equation into the adjusted body weight (ABW) by subtracting your actual body weight from the IBW. Take the difference and multiply it by 0.4. Add this number to the original value you got for the IBW to get your estimated lean body mass (ABW). Find the difference (by subtracting) between this last value and the actual body weight for an estimation of how much your fat weighs. This method is not accurate in people who are very thin or have significant non-fat mass like body builders and pregnant women.

• 2

  Do a tape measure test by taking measurements (usually at the hips and waist) and then use the results to compare your numbers to a chart (in the resources section below). Use this measurement because it is reproducible but remember that it may not be accurate for people who have different ways to store their fat (in parts of the body other than the hips and waist).

• 3

  Use calipers to grip a fat fold just above your waist to see how thick it is. Do not pinch a "roll" since it may include muscle. Just pinch the skin and fat immediately below the skin using your finger tips. Close the calipers into place over the fold, still holding the fold in your hands. When the calipers are pinching the fat, click the button on the side of the calipers or hold your finger where the measurement is located so that you can look at it when the calipers are released. The measurement will tell you the thickness of the fold and a measurement for body fat. This method is popular since it is not very expensive and can be done in private but is an estimation and carries a degree of error that depends on the tool and the technique. Read the manual for your tool before use.

• 4

  Use scales to measure body fat by measuring conductance. Step on the scale and allow the low-voltage electricity to travel through your body. Make sure that you are well hydrated and that you do not take this measurement after a shower since the moisture in your skin will alter the results. Wait for the measurement to pop up on the digital readout after stepping onto the scale. Use this method as a quick and easy way to incorporate body fat estimation into a routine since the scale converts the measurement into a body fat estimate for you.

• 5

  Estimate body fat from your body mass index (BMI) based on measuring height and weight. Use this same method whether you are male or female. Start by measuring your height and weight. Find the place where the two measurements meet on the chart (or use an online calculator). Find the number at this location and compare it to a key to see if you are obese (30 or greater), overweight (25 and up to obese), healthy (18.5 up to overweight), or underweight (less than 18.5). Check the resources for a body mass index calculator.

• 6

  Use hydrostatic weighing for the best estimation of body fat. Make sure that you have the extra money, time, and are ready for the loss of privacy as you are lowered into a tank of water in front of professionals. Use this to measure your density through displacement of water and measuring your weight. Exhale as you are lowered into the tank to displace water with the space that your body takes up. Repeat the process several times to get a good reading. Use this method only if it is critical to get an accurate measurement and if you can afford it.