Things You'll Need:
- Scale
- Measuring tape
- Calculator
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Step 1
Weigh yourself on an accurate scale. Write down your weight. Measure your height while barefoot with a measuring tape. Write your height down in inches. The formula to figure out BMI is weight divided by squared height.
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Step 2
BMI is calculated in the metric system, so convert your inches and pounds to metrics. For example, to convert the height of a person 63 inches tall, change inches to meters using this formula: 63 x .025 (the metric conversion factor) = 1.575 meters. To convert a person who weighs 125 pounds into kilograms: 125 x .45 (the metric conversion factor) = 56.26 kg.
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Step 3
Using the measurments above to calculate BMI, square the height: 1.575 x 1.575 = 2.480625. Now divide the weight by the squared height: 56.25/2.480625 = 22.7. The BMI for this person is 22.7 and is in the normal range. Substitute your metric height and weight in the above formulas to calculate your BMI.
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Step 4
Compare your BMI to the standard chart: BMI below 18.5 is considered below-normal body fat. BMI from 18.5 to 24.9 is normal fat. BMI from 25 to 29.9 is above normal and overweight. BMI at 30 or higher is obese. If your BMI is not in the normal range, you should try to lose weight.
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Step 5
BMI does not measure muscle, so if you are heavy with a lot of muscle, the BMI scale might not be accurate for you. Men and women use the same BMI chart.
