# Calculating BMI Using the English System

• Formula: weight (lb) / [height (in)]2 x 703
• Calculation: [weight (lb) / height (in) / height (in)] x 703

When using English measurements, ounces (oz) and fractions must be changed to decimal values. Then, calculate BMI by dividing weight in pounds (lb) by height in inches (in) squared and multiplying by a conversion factor of 703.

• When using a handheld calculator, if your calculator has a square function, divide weight (lb) by height (in) squared, multiply by 703, and round to one decimal place.
• If your calculator does not have a square function, divide weight by height twice, as shown in the calculation above, multiply by 703, and round to one decimal place. (Note that this formula is printed on the CDC Clinical Growth Charts, and it will be the calculation used in this module).
Example

Let’s calculate Sam’s BMI using the English numeric system. His weight is 37 pounds and 4 ounces and his height is 41 1/2 inches.

Convert ounces and fractions to decimals:

• Weight of 37 lbs and 4 oz = 37.25 lbs (16 ounces = 1 pound so 4 oz/16 oz = 0.25).
• Height = 41.5 in.

(37.25 lbs / 41.5 in / 41.5 in) x 703 = 15.2

For more detailed instructions, see Use and Interpretation of the WHO and CDC Growth Charts for Children from Birth to 20 Years of Age in the United States.Cdc-pdf

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BMI Calculator - English

1. Height:
feet
inch(es)

2. Weight:
pounds
(Note: 8 ounces = 0.5 pounds)

Results:

Practice calculating BMI by using the English system.

Complete the following two calculations, rounding to one decimal place.

• Calculation 1: Georgia’s weight is 36 1/2 pounds and her height is 39 inches. What is Georgia’s BMI?