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Calculate BMI percentile for kids and teens with our BMI Percentile Calculator. Find BMI, z-score, percentile, and CDC weight category.
The BMI Percentile Calculator helps you check a child or teen's body mass index based on age and sex. It compares BMI with other children of the same age and sex. This makes BMI percentile more useful for kids than adult BMI alone.
Our online BMI percentile calculator for kids uses the method recommended by the Centers for Disease Control and Prevention. It can help parents, students, and health professionals understand BMI percentile results with ease.
A BMI percentile calculator for pediatrics is mainly used for children and teens ages 2 to 19. Adult BMI does not use the same percentile system. Adults are usually assessed by standard BMI ranges.
First, calculate BMI with this formula:
BMI = Weight in kg ÷ (Height in meters × Height in meters)
For height in centimeters:
BMI = Weight in kg ÷ Height² in cm × 10,000
The BMI percentile calculator then uses the CDC LMS method. It needs three values called L, M, and S.
When L is not zero:
Z = [(BMI ÷ M)^L − 1] ÷ (L × S)
When L is zero:
Z = ln(BMI ÷ M) ÷ S
The BMI percentile is then found from the z-score:
BMI Percentile = 100 × Φ(Z)
Here, Φ(Z) is the standard normal cumulative distribution function.
The result shows where the child's BMI falls compared with children of the same age and sex, which can also impact bone density.
For a BMI percentile calculator CDC result, the correct age, sex, and CDC reference data are very important.
A BMI below the 5th percentile is classed as underweight.
A BMI from the 5th to below the 85th percentile is classed as healthy weight, which is also an ideal weight range.
A BMI from the 85th to below the 95th percentile is classed as overweight.
A BMI at or above the 95th percentile is classed as obesity.
Suppose a 10-year-old boy weighs 40 kg. His height is 140 cm.
First, convert height to meters:
140 ÷ 100 = 1.40 m
Now calculate BMI:
BMI = 40 ÷ (1.40 × 1.40)
BMI = 40 ÷ 1.96
BMI = 20.41 kg/m²
Next, the calculator uses the CDC LMS values for a 10-year-old boy. Suppose those values give a z-score of about 1.48.
The percentile is then:
BMI Percentile = 100 × Φ(1.48)
BMI Percentile ≈ 93.1%
So the child's BMI is about the 93rd percentile.
Since 93.1% is between the 85th and 95th percentiles, the result falls in the overweight category.
The exact result depends on the official CDC LMS values used for the child's exact age and sex.
A BMI percentile calculator for adults is not normally used in the same way as a pediatric BMI percentile calculator. Adults are generally assessed with standard BMI ranges.
For children, BMI changes as they grow. Age and sex can strongly affect BMI interpretation. This is why a BMI percentile for age calculator is used for children and teens.
A BMI percentile calculator for girls, boys, children, and pediatric patients uses age and sex-specific growth data. It is different from a simple adult BMI calculator.
The same rule applies to searches such as BMI percentile calculator female, BMI percentile calculator male, BMI percentile calculator boy, and BMI percentile calculator for girls. For pediatric use, the result must be based on the child's age and sex.
Infants under age 2 are also different. The CDC BMI-for-age percentile method described here is intended for children and teens ages 2 through 19. Infant growth assessment uses different growth standards.
A BMI at the 95th percentile means the child's BMI is higher than the BMI of about 95% of children of the same age and sex in the reference population.
Under CDC pediatric categories, a BMI at or above the 95th percentile falls into the obesity category.
A percentile is not the same as saying the child has 95% body fat. It only describes the child's BMI position within the reference group.
The BMI Percentile Calculator is a useful tool for checking BMI-for-age in children and teens. It uses height and weight to find BMI. It then compares BMI with age- and sex-specific CDC reference data.
For the best result, enter accurate measurements and use the correct CDC LMS values. Remember that BMI percentile is a screening measure. It does not diagnose a health condition by itself.
First, calculate BMI from weight and height. Then use the correct age, sex, and CDC LMS values to calculate the BMI z-score. Convert the z-score to a percentile using the standard normal distribution.
A BMI at the 95th percentile means the BMI is at or above the 95th percentile for children of the same age and sex. Under CDC categories, this is classified as obesity.
Adults usually use standard BMI categories instead of pediatric BMI percentiles. BMI percentile is mainly used for children and teens ages 2 to 19.
Yes. The calculator is designed for pediatric BMI-for-age calculations for children and teens ages 2 to 19.
Yes. Pediatric BMI percentile calculations use sex-specific reference data, so the child's sex must be selected correctly.
No. BMI is a number based on height and weight. BMI percentile compares that BMI with children of the same age and sex.