Whether you are attempting to lose weight or monitor your current bone and muscle density, the numbers shown on the scale can be misleading. While you may want to focus on the numbers of the scale, it is more important to calculate how much of your weight is unwanted fat vs. muscle and bone mass. Although it may seem you are gaining weight when you work out, calculating your muscle and bone mass can help you better determine your progress when losing unwanted pounds.
Determine your total body mass by stepping onto a scale. Make sure your scale measures in pounds or convert kilograms into pounds.
Multiply 0.15 by your total body mass to calculate total bone mass in pounds. For example, if your total body mass is 140:
140 x 0.15 = 21 lbs. of total bone mass
Obtain your body fat percentage from a trainer or doctor. Take your body fat percentage and divide it by 100 to achieve a decimal number. For example, if your body fat percentage is 10:
10 / 100 = 0.10
Multiply your body fat percentage (in decimal form) by your total body mass. This calculates your current body fat weight.
0.10 x 140 = 14 lbs. of body fat
Add your total bone mass weight and total body fat weight together and subtract the sum from your starting total weight (in pounds). This will calculate your total muscle mass.
21 lbs. of total bone mass + 14 lbs. of body fat = 35 lbs.
140 lbs. of total body mass - 35 lbs. = 115 lbs. of total muscle mass