How to Calculate BMI Weight Loss Percent

One of the most widely used measurements of an individual's fitness level is known as the body mass index (BMI). Body mass index uses an individual's height and weight to come up with a single number that is used to determine if the individual is within a healthy range of physical fitness. This index is used to determine the extent that a person's weight predisposes him or her to serious health issues. Knowledge of the BMI scale gives you the opportunity to discover whether your rating lies at a healthy point on the scale. It also lets you determine how much you need to lower your rating to reach a healthy zone.

Things You'll Need

• Body mass index calculator

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Instructions

• 1

  Decide how much weight you would like to lose. Experiment in the BMI calculator with weights that are within the healthy range. Be realistic, though. If your BMI indicates that you are obese or severely overweight, lowering your BMI by 10 to 15 points is a very long-term goal. Set smaller benchmarks for progress. (Ref. 1.)

• 2

  Calculate your BMI for your current weight. Then do the same using your desired weight. (Ref. 2.)

• 3

  Subtract the desired body mass index from your current BMI to find the difference. This offers a great way of double-checking your goal for both clarity and feasibility.

• 4

  Divide the difference between the desired and current body mass indexes by the current BMI. This is a decimal representation of the change in body mass index. Multiply this by 100 to get the BMI weight-loss percentage.

• 5

  Follow this example to get an idea of how the process works:

  For a 5-foot, 11-inch male who weighs 200 lbs., the BMI is 27.95. (Res. 1.) Let us say that his goal is to drop to 170 lbs. The BMI for 170 lbs. is 23.76. The difference between our subject's actual BMI and desired BMI is 4.19. Divide 4.19 by his current body mass index of 27.95 and you get .1499. Multiply that by 100 and you come out with a BMI weight loss percentage of 14.99.

• 6

  Begin a diet and exercise plan that is focused on decreasing your weight and BMI to the desired level. Exercise at least three times per week, including weight training and aerobic activity. Drop fatty foods from your diet and eat more lean protein to fuel muscle growth (which, in turn, feeds fat loss). Check your BMI regularly and use the formula to see how much progress you have made toward your goal. (Ref. 3.)