How to Calculate Percent of Weight Lost

The belief that any weight loss is good weight loss is a common misunderstanding. Typically, many weight watchers aim to drive the numbers on their bathroom scale down by any means. But not so fast; this strategy accounts for only part of the body weight picture. Body weight fluctuates as a result of gains or losses in the body's composition of water, fat or muscle mass. Being overweight is the product of having accumulated too much fat. Successful weight loss diminishes fat and preserves muscle. To measure your weight loss progress, keep track of inches, not pounds, lost.

Things You'll Need

• Pencil
• Paper
• Cloth measuring tape
• Calculator
• Skin-fold caliper
• Internet access
• Helper (optional)

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Instructions

Girth Measurement Formula

• 1

  Write the following on separate lines on your sheet of paper:
  For men: Upper Arm (U), Abdomen (A), Forearm (F) and Buttocks (B).
  For women: Abdomen (A), Thigh (T), Calf (C) and Forearm (F).

• 2

  Measure the girth of each of the body parts listed on your paper, placing your measuring tape around the widest circumference area of that part. The tension of the measuring tape should be snug, but not tight enough to produce skin indentations. Record your results on your paper.

• 3

  For men ages 18 to 26: Body fat percentage = U + A -- F -- 10.2
  For men ages 27 to 50: Body fat percentage = B + A -- F -- 15.0
  For women ages 18 to 26: Body fat percentage = A + T -- F -- 19.6
  For women 27 to 50: Body fat percentage = A + T -- C -- 19.6

• 4

  Follow up by retaking your measurements every two to three weeks. Keep track of your progress by subtracting your newest percentage figure from your previous percentage figure. This difference represents the percentage of fat you have lost.

Skin-Fold Measurement

• 5

  Perform your measurements while standing. Complete each measurement by first pinching the skin of the designated area between the thumb and forefinger with one hand, to pull up all the fat. With the other hand, grip your skin fold with the skin-fold calipers midway between the crest (top) and base of the fold. Round the resulting measurement to the nearest .5mm and write it down.

• 6

  For men:
  Measure diagonally halfway between the armpit and nipple.
  Measure approximately 1 inch distance to the side of the belly button.
  Measure midway between the knee and the top of the thigh.

  For women:
  Measure just above the front hip bone protrusion.
  With the arm relaxed at the side, measure the skin midway between the shoulder and elbow at the back of the arm.
  Measure midway between the knee and the top of the thigh.

• 7

  Repeat your measurements three more times to verify accuracy. If no two measurements are alike, use the median (or middle) number for that location.

• 8

  Use the Skin-Fold Calculator located in the resources below to interpret your measurements.

• 9

  Follow up by retaking your measurements every two to three weeks. Keep track of your progress by subtracting your newest percentage figure from your previous percentage figure. This difference represents the percentage of fat you have lost.