How to Determine Your Teenager's Ideal Weight

The ideal weight for teens depends largely on their body mass index, or BMI. This calculation determines the health of your teen based on his current height, weight, age and gender. According to KidsHealth.org, teens who fall in the 50th percentile of the BMI chart are considered average weight, which is the ideal for being healthy. Don't panic if your teen falls below the average weight or higher than the average weight. According to KidsHealth.org, puberty causes teen's body weight to fluctuate due to hormonal changes in the body.

Things You'll Need

• Scale
• Measuring tape

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Instructions

• 1

  Log your teen's weight in a journal to track the changes over time.

• 2

  Have your teen stand up straight against a wall, and place the metal end of the measuring tape flat on the floor. Place the measuring tape against the wall, and mark the spot directly above the teen's head to determine the height.

• 3

  Multiply your teen's weight (pounds) by 703. Next, divide that number by her height squared (in inches) and that number is her BMI. For the metric system, divide the weight (in kilograms) by the height squared (in meters). The BMI chart available at KidsHealth.org helps determines whether your teen falls into the underweight, average weight or overweight category based on age, weight and height.