A body fat percentage calculator is a program that applies information about the user to a standardized formula to obtain an estimate of the percent of the body mass that is composed of fat. The information that the formula analyzes usually includes age, gender, and height, in addition to the user’s weight and the measurement of the circumference of various body parts such as the waist and hips. In order to choose the best body fat percentage calculator, one must select the calculator that uses the most reliable and accurate formula in its calculations.
Judging the accuracy of a body fat percentage calculator can be difficult when it does not disclose the formula it uses. Some claim to use formulas based on those used by militaries. It is best to do a little bit of extra research and find a calculator that has been tested by fitness or medical professionals against the gold standard of accurately measuring body fat percentage, usually a technique known as an immersion test. An immersion test is regarded as the most accurate way to measure body fat levels, but it is only offered at medical and fitness facilities and is not a cheap or convenient enough option for the average person. Often, however, doctors and fitness professionals can recommend a body fat percentage calculator that has been proven accurate within two to three percentage points of the immersion test in clinical trials.
Many online calculators say they are accurate within two to three percentage points, but without knowing the formula, it is impossible to judge the veracity of these claims. Devices such as body composition monitors and scales that measure body fat can also estimate the body fat percentage, and will often record the results over time. Body fat calipers are also a popular option for those who can afford it or have a local gym with calipers available.
Most people, faced with the near impossibility of obtaining an accurate measure of body fat, are willing to use any free online calculator. As long as the same calculator is used over time, a fairly accurate overall change in body composition can be achieved. While this does not determine the true percentage of the body that is fat, it does allow the user to decide if a current diet or exercise plan is succeeding in building more muscle and reducing body fat, or if the trend is headed in the opposite direction.