Accurately calculate Body Mass Index (BMI) for children and teenagers. Monitor growth patterns and health categories for ages 2 to 20.
Looking for Adult BMI? Try our Men & Women BMI Calculator →
Monitoring a child's health involves more than just checking their height. Our BMI Calculator for Kids is a specialized tool designed to help parents and caregivers track the Body Mass Index of children and teenagers aged 2 to 20. Unlike adults, children's bodies change rapidly, making it essential to use an age-specific child BMI calculator to get an accurate picture of their development.
While the basic formula for BMI (weight divided by height squared) remains the same, the interpretation for children is much more complex. Because children grow at different rates and body fat composition changes as they mature, a single number doesn't tell the whole story. This is why our tool considers age and gender. If you need to verify your child's exact age for school or medical forms, you can use our Exact Age Calculator.
It is important to remember that BMI is a screening tool, not a diagnostic one. A high BMI might indicate high body fat, but it could also be due to high muscle mass or a heavy bone structure. Always discuss the results with a qualified healthcare professional. For parents managing multiple health or school tasks, our Online To-Do List can help keep track of upcoming pediatric appointments.
A healthy BMI for a child is typically defined as falling between the 5th and 85th percentile for their age and sex on the CDC growth charts. Because these percentiles change every month as a child grows, "healthy" is a moving target.
BMI calculations are generally recommended for children starting at age 2. For infants and toddlers under age 2, doctors use weight-for-length charts rather than BMI.
Most pediatricians check BMI once a year during an annual well-child visit. Checking too frequently at home can be misleading due to natural growth spurts.