How to Measure Your Body Fat Percentage
Losing fat without losing muscle mass is a great way to look lean. But, how are you going to track the fat loss, muscle loss or both?
Starting with measuring your body fat percentage is the way to go. Outlined below, you will find five different ways to measure your body fat percentage, along with the ONLY method to accurately measure body fat percentage. The methods may vary in accuracy but, the key to assessing body fat levels is with consistently taking measurements repeatedly over time to effectively track your progress.
Method 1 – Skinfold Calliper test
The “skin fold” method measures your body fat percentage by pinching your fat with your fingers then measuring the thickness with a body fat calliper. The reading is given in millimetres, which you compare to a chart with age and gender to arrive at your body fat percentage. There are many different types of calliper tests, which range from only one site like with an Accumeasure Body Fat Calliper to a 7 site Jackson Pollack Method (some can be as high as 12 sites).
Dependable (when skilled at measuring)
Variability of measurement (same exact spot needs to used each time)
More than one-site test requires a skilled fitness professional (I’ve done these thousands of times!)
For people 35+ pounds overweight, fat may not fit within the calliper, so it’s less accurate
Skin Fold is hands down the most effective, accurate, practical method to measure and track your body fat percentage. The self-administered Accumeasure Body Fat Caliper retails for under $10 and is sufficient for most people.
Method 2 – Bioelectric impedance analysis
Bioelectric Impedance Analysis, or BIA, determines the electrical impedance, or opposition to the flow of an electric current through the body. Muscle has high water content, and is highly conductive, while fat has lower water content and is not highly conductive. Based on the strength of the impedance along with height and weight metrics, the BIA scale will estimate fat-free body mass and body fat percentage.
Many consumer weight scales like the Tanita Body Fat Monitor Scale also come with BIA capabilities, and there are others that require holding the BIA device in your hands. Because the BIA test is based on body water balance, your state of hydration can impact the level of accuracy.
Very easy to administer
Inexpensive (most weight scales around $50 or even less have BIA)
Variability of results dependent on the hydration level
If you can’t use callipers, this is a far second option. If you have a high body fat percentage (callipers can’t fit around your fat pinch), or you have 35+ pounds to lose, start with BIA, then move to callipers. BIA readings for those with low body fat tend to be completely inaccurate.
Method 3 – Anthropometric
This method uses body circumference measurements to estimate body fat percentages. The U.S. Navy method takes the waist, neck, and height circumference for men and hips, neck, and height for women.
A U.S. Navy Method calculator is available on this website where you can input your measurements on the right-hand column.
Easy to Administer
Questionable Accuracy (Body fat is not directly measured)
I would consider this method the least accurate because it doesn’t directly measure body fat (or even attempt to). For example, I have around 12% body fat using callipers, but according to anthropometric, my body fat is around 20%. If you don’t have a BIA scale or callipers, it can be a decent start.
Method 4 – Hydrostatic
This method is considered the “Gold Standard” (+/- 1.5% error) of body fat measurement that requires being submerged in a specialized tank of water. Because bone and muscle are denser than water, a person with a larger percentage of fat-free mass will weigh more in the water and have a lower per cent body fat. Conversely, a large amount of fat mass will make the body lighter in water and have a higher per cent body fat.
The accuracy of the reading is contingent upon blowing all the air out of the lungs during pre-test screening. The test takes about 20-30 minutes, costs around $150-200, and is available at research labs, universities, or hospitals.
Very accurate, considered Gold Standard
Not repeatable (unless you liked repeatedly getting dunked in a tank and spending $150)
If you are extremely curious to get the most accurate measure of your body fat percentage, or you are a bodybuilder, or fitness model tracking your progress, Hydrostatic Weighing may make sense. Otherwise, it’s far too impractical.
Method 5 – DEXA Scan
Dual Energy X-ray Absorptiometry known as DEXA is fast becoming the “new” gold standard of body fat measurement because it’s based on a three-compartment model that divides the body into total body mineral, fat-free soft (lean) mass, and fat tissue mass. Hydrostatic Weighing on the other hand only uses a 2-compartment model (fat-free mass and fat mass).
DEXA also allows for body fat distribution analysis, so you can figure out with precision how fat is distributed in various parts of your body. In the past, DEXA was only used to measure bone mineral density for osteopenia and osteoporosis in older individuals. The procedure uses a body scanner with low dose x-rays, so it’s completely safe and takes about 10-20 minutes.
I have personally had a DEXA scan from the team at BodyMeasure and they do metabolic testing too!
Expensive: From $90 to upwards of $250 in various locations
Not repeatable (unless you don’t mind spending the amount every couple of weeks)
Similar to Hydrostatic Weighing, if you are extremely curious to get the most accurate reading of your body fat percentage, or you are a bodybuilder, or fitness model tracking your progress, DEXA may make sense. Otherwise, it’s far too impractical and expensive.
All these methods rely on algorithms to convert a measured parameter into an estimate of body fat percentage, so none of them is absolutely perfect. Algorithms have variation based on how the underlying assumptions and formulas apply to different populations.
So, what’s the only way to measure body fat with perfect accuracy? Well, cutting open a body and examining the fat, like with a cadaver. Seriously, that’s really the only way to measure body fat percentage most accurately.
I will be digging deeper into each method and bring you future articles on each, but I hope this was a helpful overview of each method.