How to Calculate Your Body Fat Percentage Using a Tape Measure
Chris enjoys writing about a variety of topics including science, health, and fitness.
Wouldn’t be nice to be able to determine your body fat percentage without the use of expensive scales, special devices, or traveling to see the doctor? Well, there is a way that it can be done with a only little bit of math and some measurements of your body. Scientists and fitness experts have developed several empirical formulas which can be used to estimate a person’s body fat percentage using a tape measure in lieu of directly measuring it. Even though these methods aren't as accurate as a water displacement test or the "bod pod", they are still a good estimate of body fat percentage. They typically only have an error of +/-3%.
For comparison, here is a table of the of body fat percentage categories.
Women (% fat) | Men (% fat) | |
---|---|---|
Essential Fat | 10-13% | 2-5% |
Typical Athletes | 14-20% | 6-13% |
Fitness (In Shape) | 21-24% | 14-17% |
Acceptable | 25-31% | 18-25% |
Obese | 32%+ | 25%+ |
Method #1: Covert Bailey Method
This method is probably the newest method available. To use this formula, you need to obtain several measurements of your body.
Women's Formula
To compute a woman's body fat percentage using this method, you will need to measure 4 different factors: A) Hips, B) Thigh, C) Calf, and D) Wrist. All measurements should be taken at their widest points and should be recorded in inches.Fat% = A+0.8B - 2C - D (for Women 30 years old or younger)
Fat% = A+ B - 2C - D (for Women over age 30)
Men's Formula
The measurements needed to compute body fat percentage using the Covert Bailey Method for a male are: A) Hips, B) Waist, C) Forearm Circumference, and D)Wrist. All measurements should be taken at their widest points and should be recorded in inches.Fat% = B + 0.5A - 3C - D (for Men 30 years old or younger)
Fat% = B + 0.5A - 2.7C - D (for Men over age 30)
For more information about this method, please refer to Covert Bailey's 1999 book called "The Ultimate Fit or Fat."
Method #2: Department of Defense Formula (aka US Navy Circumference Method)
Everyone knows that you must meet certain physical characteristics if you want to join the military. What many people don't realize is that body fat percentage is the main criteria for acceptance and not weight. When getting ready to sign up, the formula's shown below are used to determine a person's eligibility to join.
Women's Formula
To compute a woman's body fat percentage using this method, you will need to measure 5 different factors: A) Height, B) Neck Circumference, C) Waist (smallest point) and D) Hips (at the fullest point). All measurements are in inches. Note that by using this method, the waist measurement must be taken at the smallest point which is usually found halfway between the sternum and naval.Fat% = 163.205 × Log_{10}(C + D - B) - 97.684 × Log_{10}(A) - 78.387
Men's Formula
The measurements needed to compute body fat percentage using the Department of Defense Method for a male are: A) Height, B) Neck Circumference, and C) Waist (at navel). All measurements are in inches.Fat% = 86.01 × Log_{10}(C - B) - 70.041 × Log_{10}(A) + 36.76
Method #3 Heritage BMI to Body Fat Percentage Method
This method is very simplistic as the only variables needed are your age and your Body Mass Index (which is a function of your height and weight). Please note that for people with BMI's over 30, this formula begins to overestimate body fat percentages.
Women's Formula
To compute a woman's body fat percentage using this method, you will need to know 2 different factors: A) age, B) BMI. Age should be in years.Fat% = 1.39B + 0.16A - 9
If you don't want to calculate your BMI first before using this formula, then can directly calculate your body fat percentage using these variables instead: A) Age, B) Weight, and C) Height. A measurements should be in inches, lbs, and years. The modified Heritage formula becomes:
Men's Formula
To compute a man's body fat percentage using this method, you will need to know 2 different factors: A) age, B) BMI. Age should be in years.Fat% = 1.39B + 0.16A - 19.34
If you don't want to calculate your BMI first before using this formula, then can directly calculate your body fat percentage using these variables instead: A) Age, B) Weight, and C) Height. A measurements should be in inches, lbs, and years. The modified Heritage formula becomes:
Method #4: YMCA Method
This method was developed by the YMCA as a simple way to estimate your body fat percentage using only your weight and your waste circumference.
Women's Formula
To compute a woman's body fat percentage using this method, you will need A)Waist Circumference, and B)Weight. All measurements are in inches and pounds.
Notice that the numerator in the above equation is the amount of fat in pounds that your body has.
Men's Formula
To compute a man's body fat percentage using this method, you will need A)Waist Circumference, and B)Weight. All measurements are in inches and pounds.
Notice that the numerator in the above equation is the amount of fat in pounds that your body has.
Method #5: Modified YMCA Method
Women's Formula
To compute a woman's body fat percentage using this method, you will need to measure 5 different factors: A) Total Body Weight, B) Wrist Circumference, C) Waist (at navel), D) Hips (at the fullest point), and E) Forearm Circumference. All measurements are in inches and pounds.
Notice that the numerator in the above equation is the amount of fat in pounds that your body has.
Men's Formula
This method is easier for men because it only requires two measurements to calculate an accurate measurement of body fat. The measurements needed are: A) Total Body Weight, and B) Waist Circumference. All measurements are in inches and pounds.
The numerator in the above equation is the amount of fat in pounds that your body has. Note that this formula is nearly the same as the regular YMCA Method.
Comparison of These Methods to a Real Measurement
A couple of years ago I had a complete physical done on me. During the physical, my doctor estimated my body fat percentage to be about 26.5% using a NIR (Near Infrared Interactance) device. This machine was placed on my right bicep and measured my body fat percentage in seconds. In addition to this, I obtained measurements of my body (Weight=208lbs, Height=69in, Waist=40in, Neck=16.5in, Hips=52in, Wrist=6.5in, Forearm=11.5in) for my use. The table below shows my measured as well as my calculated body fat percentages at that point in time.
Method | Percentage |
---|---|
NIR Device | 26.50% |
Covert Bailey Method | 25.00% |
Department of Defense Method | 25.90% |
Heritage BMI to Body Fat Method | 27.20% |
YMCA Method | 24.30% |
Modified YMCA Method | 26.20% |
Average (Computational Methods) | 25.70% |
Range (Computational Methods) | 24.3-27.2% |
It's interesting to note that all of the methods are within the expected +/- 3%. The Modified YMCA Method was the most accurate for my body with the Department of Defense Method trailing close behind it. I was surprised to find that the YMCA Method was less accurate than the Heritage Method.
Which Method is Best?
It must be noted that no empirical formula is perfect. In reality, there are many more variables that affect body fat percentage then just the simple things that are being measured for these equations. For me, the most accurate method was the Modified YMCA Method. However, most people will likely tell you that the Department of Defense Method or the YMCA Method are the most accurate. Yet others swear by Covert Bailey's method. Personally, I like to try all the methods and see what the average value and the range is. Based on that information, I can get a pretty good idea of what my body fat percentage really is. Keep in mind that all of these equations, like anything else, has some general limitations:
- These equations are generally not applicable for children or those under the age of 18
- These equations may incorrectly calculate body fat percentages for the elderly, sick, and highly athletic
Tips for Measuring your Body
Care should be taken to ensure that your measurements are taken accurately. This will help to ensure that the equations compute in the most accurate estimate of body fat percentage that is possible.
- Do not use a measuring tape that is old or stretched out.
- All measurements should be taken when the body is in a relaxed state.
- Multiple measurements should be taken and then averaged to avoid creating a large error.
- Measurements should be taken in the morning after having a full night’s rest
- Unless otherwise noted, measurements should be taken at the widest point of their specific area.
References and Resources
^{Bailey, Covert. The Ultimate Fit or Fat. Houghton Mifflin Company. 1999Filingeri, Vincent S. PhD. Fat Control: The NET Equation. First Edition Publishing. 2011Jackson AS, Stanforth PR, Gagnon J, et al. The effect of gender, age and race on estimating percentage body fat from body mass index: the Heritage Family Study. June, 2002. <http://www.halls.md/>US Department of Defense. The Army Weight Control Program. June 2011. <http://www.armyg1.army.mil/hr/weight/docs/600-9_FAQs.pdf>Rivera, Hugo. Body Fat Calculator: How To Calculate Your Bodyfat Percentage. 2011. <http://www.davedraper.com/bodyfat-calculation.html>Zim, Steve, Steinberg, Steve. The 30 Minute Celebrity Makeover Miracle: Achieve the Body You've Always Wanted. John Wiley and Sons, Inc. 2008}
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
Comments
Ben Knights on July 19, 2015:
This is really useful content, i didnt know there were so many ways to calculate the percentage
Kristen Howe from Northeast Ohio on June 16, 2015:
Great hub on the different ways you can calculate your BMI. It looks so complicated by doing it long hand, since I'm not good in math. Voted up!
Christopher Wanamaker (author) from Arizona on November 06, 2013:
I prefer technology too, however it's not always practical or economical. Equations can give you a good estimate to start with.
Alfin Loencontre on November 06, 2013:
Prefer technology
John on October 20, 2013:
The heritage BMI to Body Fat Calculator seems to be more inaccurate than BMI, considering it is actually telling people to go lower than even BMI does. For my age, 18, it says a healthy BMI (6.0% - 17.9% body fat) would be from 16.2 to 24.7, which is not that far off from the 18.5-24.9 range, although it allows for people who are anorexic (below 17.5) or near severely underweight (almost below 16) to be considered to have an athletic body fat percentage, in other words, healthy. However, as you get older, the range that is considered healthy gets lower and lower. For example, at age 30, the "healthy" range is calculated to be 14.8 to 23.4, and at 40, that range is 13.7 to 22.2, thus allowing very severely underweight individuals (below 15) be considered "healthy," while a significant portion of the upper healthy range is considered "overweight." Even worse, if you consider elderly people, say 70, they are calculated to have a healthy body fat percentage with a BMI of 10.2 to 18.8, which means that only the lowest 4 healthy BMI numbers (18.5-18.8) are considered healthy by that age, and people are allowed to go down to dangerous BMIs as low as 10.2. To put that in terms of weight, a 6' man, for example, would be considered healthy at 119.5-182.1 lbs at 18, 109.2-172.5 at 30, 101.1-163.7 at 40, and 75.3-138.6 by the time he's 70. Therefore, the BMI to body fat method is very inaccurate.
However, all of the other calculations seem pretty accurate. For me, I have determined the most accurate to be the YMCA method, followed extremely closely by the Department of Defense method. I have determined that the YMCA method actually has a degree of error of about 0.001% for me as compared to skinfolds. Basically, this is how the calculations come out for me along with the degree of error compared to skinfolds in parentheses: Covert Bailey Method: 13.000% (-1.028%); Department of Defense Method: 13.903% (-0.125%); BMI to Body Fat Method: 21.829% (+7.801%); YMCA Method: 14.029% (+0.001%) and Modified YMCA Method: 16.112% (+2.084%).
Christopher Wanamaker (author) from Arizona on September 25, 2012:
Claudio - Yes you are correct - Thanks for reading!
Claudio Carta on September 25, 2012:
The heritage BMI Calculator was the most inaccurate for me. And gave me around 7% margin of error. I think it's mainly because of the lean muscle.
Also isn't the YMCA method calculated by dividing by Weight rather than waist?
Great post however Thanks
kjrzeek1 from New Jersey, USA on July 16, 2012:
Nice Hub. That is a lot of information, and I never realized there were that many ways to measure body fat!
Christopher Wanamaker (author) from Arizona on May 28, 2012:
Totalhealth - I am glad that you found this article useful. There are actually a few other lesser known methods for calculating your body fat percentage. However, these 5 seem to be the most well known and most accurate.
TotalHealth from Hermosa Beach, CA on May 28, 2012:
Interesting read. Never realized the numerous options available to measure body fat. Thanks!
Christopher Wanamaker (author) from Arizona on November 03, 2011:
Stephaniedas - Thanks for reading! I actually expected some of the equations to be more complicated than what I have presented here. It was also surprising to me to see how accurate they actually were.
Stephanie Das from Miami, US on November 03, 2011:
This is really interesting that you can do it using body proportions. I always knew it could be done, but Ive never seen how. Voted up and interesting.