Bodyfat Calculator

Measuring your bodyfat is the most accurate way of determining health. Most people use a bathroom scale to find out if they need to lose a couple of pounds. But the number on a scale gives can be deceiving.

All a scale can give you is your total body weight. In and of itself that means little. Total body weight is composed of bodyfat, lean muscle, and the skeletal system.

A person can be skinny--a lightweight--and at the same time, very unhealthy. For example, a man who weighs 160 pounds but has 21% bodyfat is unhealthy. But a man who weighs 160 pounds with 13% body fat is very healthy.

It is the amount of lean body weight which determines health. The average American is overweight (66%), and of that number, 33% are obese. This means that their body fat is too high in comparison to their lean body weight.

There are many ways of finding out your body fat percentage: hydrostatic (underwater or immersion), skin calipers, electrical impedance, and taking key body part measurements with a tape measure, and plugging the results into a formula.

The gold standard and most accurate of all methods is hydrostatic weighing. This is based on the principle that since muscle is denser than fat, it will tend to sink in water. Underwater weighing is very expensive and not accessible to the general public.

Using skin fold calipers to compute bodyfat is popular. Fat within the skin is measured in several key parts such as the back of the upper arm and the waist. The results are then plugged into a formula. Though not as accurate as hydrostatic weighing, it is inexpensive. One downside is that a person needs to fairly skilled in the use of calipers.

Electrical impedance is the principle used in electronic scales and hand held devices. This is based on the fact that muscle contains more water than fat, and it conducts electricity easily.

The final and cheapest method to find out your body fat levels is to use a tape measure. Waist, thigh, forearm (with clenched fist), hip, calf, and wrist measurements are taken. Together with your gender (male or female) and age, a fairly accurate fat percentage can be calculated.

The margin of error of this method is fairly small. For instance, if your measurement was 17%, your true percentage can be anywhere from 15% to 19%.

This method along with electrical impedance can give inaccurate results for the highly fit (like a bodybuilder) and the skinny but unfit person. For the very fit, the percentage will be 3 to 5% higher than calculated; for the skinny and unfit, it will be 3 to 5% lower than calculated.

The method used here is taking key bodypart measurements with a cloth tape measure. These numbers, along with age and gender, are then plugged into a formula.

Following is a table of fat percentages by race and gender. Race is a factor because the bones of African-Americans tend to be more dense than those of Asians or Caucasians. One the other hand, the bones of Asians are light and porous.

OK, you now have your body fat percentage. But what exactly does it mean? Let's suppose that your weight is 180 pounds and your calculated body fat is 18%. First convert 18% to a decimal. It becomes 0.18.

Multiply 0.18 by your weight. 0.18 * 180 pounds= 32.4 pounds. That means 32.4 pounds of your total weight of 180 pounds is pure fat. Your lean body mass is 180 pounds (total body weight) minus 32.4 pounds (fat), or 147.6 pounds.

Return to Home Page from Bodyfat...