Calculating Body Fat Percentage

neelia

Anyone know of a simple way to calculate Body Fat Percentage?

Thanks!

sugarbuzz74

I have a Body Fat monitor (http://www.healthstatus.com/blog/bodyfattesting/omron-2/omron-hbf-306c-fat-loss-monitor-black/) and it works great. I saw a nutritionist for awhile and she highly recommended this one.

DelawareGal

The best way is with a set of calipers, but if you don't know how to use them properly you can get a very inaccurate reading. .Another way is to get a scale that measures your body fat. Fairly accurate. Last choice is to use the tape measure method. Keep a log and every couple of weeks, take measurements again. Here is a site that converts measurements into %.

http://www.linear-software.com/online.html
(cut & paste into your browser)

Scroll down for the womens measurements. You can also input measurements from calipers and get a reading. Very good info. Note: this is for adults only, results vary if using this for children under the age of 14. They require a special table.

hpsnickers1

I purchased a caliper and tape measure at Amazon for $9 dollars. It comes with a chart and I'm happy with it. Even if it's slightly inaccurate you get your starting point and then you can go from there. Just like a scale that is off. The first time you step on it the number might be off but if you are losing weight then you will see the scale drop regardless.

Mine was at 20mm (around 30%). A week later it dropped to 19mm. I'm trying to do the same spot every time and I will check a few times to see if I get the same number. It came with a picture showing where to pinch.

ashlee954

Simple? No. But there are several sites where you can enter in all of your measurements (ie waist, hips, chest) and they do the calculation for you. Otherwise it is a series of equations. Ehow has this as how to do it yourself:
1) Weigh yourself on an accurate scale and write down your total weight in pounds. Measure the girth of your waist with the measuring tape. Wrap it around at the waist line, or just under the navel. Write down your results in inches.

2) Multiply the girth of your waist by 4.15 using the calculator, and write down the result, labeling it as "result 1."

3) Multiply your body weight by 0.082 using the calculator, and write down the result, labeling it as "result 2."

4) Subtract result 2 from result 1, and write down the answer as "result 3."

5) Subtract 76.76 from result 3 if you're a woman. Subtract 98.42 from result 3 if you're a man. Write down the answer to this equation as "result 4."

6) To calculate body fat percentage, divide result 4 by your body weight. Multiply the result by 100 to get your average body fat percentage.

Kate_UK

My scale caluclates mine, although I'm not sure how accurate it is

andreamichelle82

Posting on this so I can check this site out later! Thanks for the tip

bbygrl5

My scale calculates mine, but I know it can be inaccurate as much as 5-15% I use it more as a progress tool, because the measurement has been decreasing steadily over time.

hpsnickers1

Simple? No. But there are several sites where you can enter in all of your measurements (ie waist, hips, chest) and they do the calculation for you. Otherwise it is a series of equations. Ehow has this as how to do it yourself:
1) Weigh yourself on an accurate scale and write down your total weight in pounds. Measure the girth of your waist with the measuring tape. Wrap it around at the waist line, or just under the navel. Write down your results in inches.

2) Multiply the girth of your waist by 4.15 using the calculator, and write down the result, labeling it as "result 1."

3) Multiply your body weight by 0.082 using the calculator, and write down the result, labeling it as "result 2."

4) Subtract result 2 from result 1, and write down the answer as "result 3."

5) Subtract 76.76 from result 3 if you're a woman. Subtract 98.42 from result 3 if you're a man. Write down the answer to this equation as "result 4."

6) To calculate body fat percentage, divide result 4 by your body weight. Multiply the result by 100 to get your average body fat percentage.

Would right underneath your navel be the smallest part of your waist? I'm short waisted. the smallest part of my waist is about a half inch above my navel. The top of my pelvis is in line with my navel.

EDIT: I just did this using my existing measurement and weight and it is almost dead on with my caliper reading.

ArchyJill

I have read that calipers are least accurate because of error in duplicating the measurement. I have a scale that claims to measure body fat but I am pretty sure it is just giving me readings based on lower body (I got a DEXA scan and the fat percentage overall didn't match but lower body did). I am getting an Omron 306, there is still a margin of error but not as crazy as the other methods.

TrainingWithTonya

None of the ways of determining body composition are 100% accurate or comparable to each other. So, whatever method you pick, stick with it to compare results to be able to monitor changes over time. So, in order of accuracy (most accurate to least accurate), here are some bits of info on the various body composition analysis methods.

DEXA Scan: This is like getting an x-ray or CT scan of the whole body. It literally looks at the inside of the body to see what is fat and what is bones, muscles, etc. The drawback to this method is that it assumes that each part of the body is symmetrical all the way around and that isn't necessarily true. For example, some people have larger quadriceps muscles on the front of the legs and more fat around the hamstrings on the back of the leg, or more fat in the stomach then in the low back. Another drawback is that it does use x-rays to determine body fat, and excessive exposure to them can be harmful. Plus, depending on where you live they may or may not be accessible or affordable.

Hydrostatic Weighing: This is a measurement of what you weigh underwater by measuring water displacement based on the fact that fat has less density then water and muscle, bones, etc. have a higher density so you are essentially only weighing the muscle, bones, etc. in the body. It has been the gold standard of body composition testing for years, but has recently been surpassed by DEXA scanning. The drawbacks are that you have to wear very little clothing while in a lab setting, plus you have to exhale all the air possible and hold your breath while under water to get an accurate reading. Generally, it is only accessible in a lab setting so it can be financially inaccessible.

Bod Pod: This is a measure similar to hydrostatic weighing only it uses the weight of the body and the air displacement of the body to determine body composition. The drawbacks to this are similar to the hydrostatic weighing. This is also hard to get to in some areas, although some large cities now have more accessible versions.

Bio-Electrical Impedance: This is the technology used by the body fat scales and the handheld devices such as the Omron mentioned earlier. It basically uses an electrical current running through the body to estimate body fat because fat is not as conductive as muscle, bones, water, etc. in the body. There are several different versions of bio impedance though. The most accurate is the version in some gyms that uses an electrode at the hand and another at the foot so that the current goes through the full length of the body. The scale version would be the next most accurate because it measures from foot to foot so that the current flows through the midsection and lower limbs, which is where most people store most of their fat. That being said, it can give a higher reading then the actual body fat % because it assumes that the whole body is just as fat as the area where the current flows. The least accurate is the handheld device because the electrical current flows from hand to hand and through the shoulder region of the body. The reason it is the least accurate is that most people don't carry as much body fat in this area then they do lower in the body, so it will give a lower body fat reading then is actually in the whole body. Because of the differences in the way they determine body composition, there are different charts for what an acceptable body fat is based on the piece of equipment used, so if you choose one of these methods be sure to go by the chart in the book that comes with it. The drawbacks of this method are that hydration level can effect the reading quite a bit. So, if you use this measurement, make sure you are drinking plenty of water, haven't worked out in 12 hours, and don't compare measurements at different times in the menstrual cycle.

Calipers: Calipers determine body fat based on pinching skinfolds at various places on the body. If you use a formula that uses more skinfold sites on the body it is more accurate then the 1 or 3 site formulas, but they still only measure body fat at the skin level. The drawbacks are that they can't "see" the body fat around the organs (which is the most dangerous body fat) so their accuracy is a lot lower then the other methods. Also, there is a lot of variability in the skill level of the people using the calipers. They can artificially decrease body fat readings by pinching too hard or artificially increase body fat readings by pinching muscle in with the fat. Although they are available at any local supplement shop or online for anyone to use, they should only be trusted when used by someone who is specially trained in using them and can only be compared to their previous measurements if done by the same person due to variability in how each person does the measurements.

Measurements / Measurement Formulas: These are the least accurate for determining body fat because they can't tell if they are measuring muscle or fat, but they are great for seeing losses not shown on the scale. The formulas used to turn measurements into body fat % vary in accuracy so if you choose this method, be sure to stick with the same formula. This is probably the least expensive way of estimating body composition, but is also the least accurate, so you have to weigh your options. From the ACE Personal Trainer Manual here are the formulas for figuring this way:

Body Density for Women = 1.168297 - (0.002824 x abdomen in centimeters) + (0.0000122098 x abdomen in centimeters squared) - (0.000733128 x hips in centimeters) + (0.000510477 x height in centimeters) - (0.000216161 x age)

Body Density for Men = 1.21142 + (0.00085 x weight in kilograms) - (0.0005 x iliac measurement in centimeters) - (0.00061 x hip in centimeters) - (0.00138 x abdomen in centimeters)

Once you have body density you get percent fat with the following formula (495 / Body Density) - 450

For the mens formula the iliac measurement is the measure around the body at the iliac crest (the bony part of the pelvis at the top).

Alioth

Bump

I just compared my body fat percentage estimates with my new scale, Navy circumference formula, and YMCA circumference formula. 3 different calculations--3 different results. This is a confusing issue, and important to understand.