Built in bodyfat calculator from circumference measurments
Most clients do not have access/ability to measure bf. Electrical impedence devices are questionable and vary greatly based on many factors. Please allow the system to generate bodyfat based on entered circumference measurements. There are many formulas available. I have inserted the US Military and the even newer Ace (American Council on Exercise) formula below:
Military:
For men, use the following formula: % body fat = 86.010 x log10(abdomen  neck)  70.041 x log10(height) + 36.76 [8]
For women, use the following formula: % body fat = 163.205 x log10(waist + hip  neck)  97.684 x log10(height)  78.387
ACE:
For Men:
Before you use the formulas, there are two measurements that are required:
Measurement 1: Bodyweight
Measurement 2: Waist Girth (measured at the umbilicus)
Procedure:
1) Multiply your bodyweight by 1.082. Add the result to 94.42. Once your calculation is complete, save the number. à (Bodyweight x 1.082) + 94.42=Result 1
2) Multiply your waist girth by 4.15. Once you get this result, subtract it from the number obtained in step 1 (ie: Step 1 resultStep 2 result). The result obtained after the subtraction is done is your lean bodyweight (your weight if you had no fat in your body at all). à Result 1  (Waist Girth x 4.15)= Lean Body Weight
3) Finally, subtract your lean bodyweight from your total bodyweight (Total weightLean Bodyweight). Once you get the result, multiply that number by 100. Once you get the result divide it by your total bodyweight. This final result is your percentage of body fat. à ((Total Bodyweight  Lean Bodyweight) x 100) divided by (Your Body Weight) = Your Percentage of Body Fat.
Example:
I weigh 190 and I have a 30.5inch waist. Therefore, step 1 is (190 x 1.082) + 94.42 = 300. Step 2 says that my lean body weight equals 300(30.5 x 4.15)=173.425. Finally, Step 3 says that my body fat percentage is ((190173.425) x 100) divided by 190= 8.72%.
For Women:
Before you use the formulas, there are five measurements that are required (not fair, I know):
Measurement 1: Bodyweight.
Measurement 2: Wrist Circumference (measured at the widest point).
Measurement 3: Waist Circumference (measured at your umbilicus).
Measurement 4: Hip Circumference (measured at the widest point).
Measurement 5: Forearm Circumference (measured at the widest point).
Procedure:
1) Multiply your bodyweight by 0.732. à Bodyweight x .0732 = Result 1.
2) Add the result above to 8.987. à Result 1 + 8.987= Result 2.
3) Divide your wrist circumference by 3.14. à Wrist divided by 3.14 = Result 3.
4) Multiply your waist measurement by 0.157. à Waist x 0.157 = Result 4.
5) Multiply your hip measurement by 0.249. à Hip x 0.249 = Result 5.
6) Multiply your forearm measurement by 0.434. à Forearm x 0.434 = Result 6.
7) Add results 2 & 3. à Result 2 + Result 3 = Result 7.
8) Subtract Result 4 from Result 7. à Result 7  Result 4 = Result 8.
9) Subtract Result 5 from Result 8. à Result 8  Result 5 = Result 9.
10) Add Result 6 and Result 9. The result is your lean body mass (your fat free weight) à Result 6 + Result 9 = Lean Body Mass.
11) Subtract your lean body mass from your bodyweight. Once you get the result, multiply that number by 100. Once you get this result, divide it by your bodyweight. à ((BodyweightLean Body Mass) x 100) divided by your bodyweight.
Example:
A woman that weighs 125, and has a wrist measurement of 6.0, a waist measurement of 24, a hip measurement of 38, and a forearm measurement of 9.5 would calculate her body fat percentage in the following manner. Step 1: 125 x 0.732=91.5. Step 2: 91.5 + 8.987=100.487. Step 3: 6 divided by 3.14=1.91. Step 4: 24 x 0.157=3.768. Step 5: 38 x 0.249=9.462. Step 6: 9.5 x 0.434=4.123. Step 7: 100.487+1.91=102.397. Step 8: 102.3973.768=98.629. Step 9: 98.6299.462=89.167. Step 10: 4.123+89.167=93.29 (Lean Body Weight: Fat Free Weight). Step 11: ((12593.29) x 100) divided by 125 = (31.37 x 100) divided by 125 = 3171 divided by 125= 25.368 (Body Fat Percentage).
1 comment

Anonymous commented
The Navy has a very simple one that uses Height Weight Waist and Neck girth. Pretty accurate ~3% +/