How to Calculate Your Ideal Body Fat Percentage

5 easy steps to find out how much weight you can lose healthily

Body fat percentage is the percentage of your weight that is made up of fat. It consists of both storage body fat and essential body fat. There are several ways to calculate your body fat percentage, including bioelectrical impedance analysis, skinfold methods and other anthropometric methods, or methods involving the circumference of various body parts. Here's a method to calculate your body fat using only your scale and a calculator.

Step 1: Know the recommended body fat percentile ranges

The first step in beginning the process of understanding how to calculate your ideal body fat is to consider variables such as body type, heredity, age, activity and gender. For instance, healthy body fat percentage ranges for women tend to be higher than those for men, as women need more body fat. A certain amount of fat is important for bodily functions. It regulates your body temperature, cushions organs and tissues and is the main form of your body’s energy storage. So it's important that you don't have either too much or too little body fat. Mayo Clinic staff, as well as other health professionals, list the following age-adjusted body fat percentile recommendations:


  • 20-40 yrs old: Underfat: under 21 percent, Healthy: 21-33 percent, Overweight: 33-39 percent, Obese: Over 39 percent

  • 41-60 yrs old: Underfat: under 23 percent, Healthy: 23-35 percent, Overweight : 35-40 percent Obese: over 40 percent

  • 61-79 yrs old: Underfat: under 24 percent, Healthy: 36-42 percent, Overweight: 36-42 percent, Obese: over 42 percent


  • 20-40 yrs old: Underfat: under 8 percent, Healthy: 8-19 percent, Overweight: 19-25 percent, Obese: over 25 percent

  • 41-60 yrs old: Underfat: under 11 percent, Healthy: 11-22 percent, Overweight: 22-27 percent, Obese: over 27 percent

  • 61-79 yrs old: Underfat: under 13 percent, Healthy: 13-25 percent, Overweight: 25-30 percent, Obese: over 30 percent

Step 2: Weigh yourself

Obtain as accurate a body weight as possible. Different scales often give different numbers, and depending on the time of day you weigh yourself, your numbers may vary. Try weighing yourself on the same scale at approximately the same time of day over a few days to get an average of your body weight.

Step 3: Calculate your body mass index (BMI)

You can easily calculate your BMI by dividing your weight in pounds by your height in inches squared, and then multiplying by a conversion factor of 703. Using the example of a 150-pound person who is five feet five inches (or 65 inches), the calculation would look like this: [150 ÷ (65)²] x 703 = 24.96

Step 4: Calculate your body fat percentage

According to a study published in the British Journal of Nutrition in 1991, if you are an adult, your percentage of body fat can be estimated as accurately as with skinfold measurements and bioelectrical tests using the following gender-based formulas in conjunction with your BMI. This calculation has been shown to slightly overestimate body fat percentage in people who are very overweight. Take your BMI result from Step 3 and plug it into the appropriate formula below to calculate your body fat percentage.


  • (1.20 x BMI) + (0.23 x Age) - 5.4 = Body Fat Percentage


  • (1.20 x BMI) + (0.23 x Age) - 16.2 = Body Fat Percentage

Step 5: Compare your body fat percentage to the percentiles listed in Step 1

Take a moment to compare the result you got in Step 4 to the body fat percentiles in Step 1. Comparing your results with these numbers should give you a good indication of how close or how far you may be from your ideal body fat percentage.


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jlb392's picture
User offline. Last seen 1 year 34 weeks ago. Offline
Joined: 09/04/2014

ummmm....that calculation?

"if you are an adult, your percentage of body fat can be estimated as accurately as with skinfold measurements and bioelectrical tests using the following gender-based formulas in conjunction with your BMI. This calculation has been shown to slightly overestimate body fat percentage in people who are very overweight."

Not even close. If you're muscular, it's going to be WAAAAAY off. I just had the 7 site Jackson Pollack Method done yesterday and I'm at 23.2%. However, because of the amount of muscle I have, my BMI is around 27. According to the formula above, my body fat is around 40%, which is most definitely not the case.

TLDR: BMI (and anything that uses BMI as a means to measure something else) is BS. If you aren't able to get a 7-site pinch test, at least get yourself a body fat caliper. You can find a decent one for around $10 and use it to check your abdominal area- that will give you a pretty close estimate.

JonathanLB's picture
User offline. Last seen 1 year 8 weeks ago. Offline
Joined: 03/08/2015

While I appreciate some of the information here -- namely the body fat percentage guides -- I think it's extremely important to point out how inaccurate the BMI is for a large subsection of the population, especially healthy men, and that using the BMI in any equation is a completely terrible idea. For instance, let me show you how mine worked out. I'm 167 pounds, 5'10", so after plugging my numbers into the equation (I knew it would be hilariously far off, but it was entertaining), it returned 19.9% body fat, so almost 20%! In point of fact, I am about 10% body fat exactly. Your equation only works for people with average or below average muscularity. For me, I bench 225 for reps and my one rep max is well above 250 pounds, so the BMI is not an accurate measurement of my fitness. In fact, I could be "overweight" on the BMI scale and at an average body fat percentage. For any muscular guy, the BMI is highly inaccurate, which means for most fit guys, it simply doesn't get the job done in predicting fitness or health. Using it to calculate body fat percentage is just all sorts of wrong. In my example, it takes a body fat percentage that's in the "athlete" close to "elite" range and instead puts me in the "overweight" range, which makes that calculation useless. That should truly be noted in the article!

Anonymous's picture

Fully agree with the above comments - the "calculator" is useless since it uses a highly suspect factor of BMI. The results are useless!

Anonymous's picture

This calculator is way off for determining body fat percentage as the other reviers have said. This could be very discouraging for someone who is athletic but new to these measurement techniques. From an electronic scale I am 21%, 7 pt Jackson calipers say I'm 18.5% and this calculation says I'm 26%. I have visibly defined muscles in my abs, thighs, legs... check out some pictures online of the difference between 18-20% and 26% on a female. I can't believe professionals would still rely on BMI anyway. I should have known but was curious. If you never exercise or have minimal muscle definition this might be accurate for you.

Anonymous's picture

I agree. This is waaaaaaay off. I just got my fat measured to be at 19.1% by a pro and this calculation is saying I'm at 28%???? Downright wrong. I'm 116#, 5'5" and there's no way I could be at 28% fat!

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