How to Calculate Infant BMI

According to harvardscience.harvard.edu, "Rapid weight gain during the first six months of life may place a child at risk for obesity by age 3." Assessing whether your infant's weight is healthy in relation to his height and length can be done by measuring the infant's body mass index. According to kidsdirect.net, your infant's BMI should not be above 20. The National Center for Chronic Disease Prevention and Health Promotion provides a formula for calculating the body mass index of an infant.

Things You'll Need

• Infant scale
• Tape measure
• Calculator

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Instructions

• 1

  Weigh your infant, using a baby scale, in pounds.

• 2

  Measure your infant from head to toe using a tape measure. Record the baby's length in inches.

• 3

  Divide your infant's weight in pounds by her height in inches.

• 4

  Divide the quotient from the previous equation by your infant's height in inches again.

• 5

  Multiply the quotient from the previous step by 703. The result of this equation will provide you with your infant's BMI.

  Here is an example:

  If an infant weighs 10 lbs. and measures 22 inches from head to toe, then the following equation will calculate the infant's body mass index.

  10 ÷ 22 ÷ 22 x 703 = 14.5