Bmi Percentile Calculator

Use this calculator to determine your Body Mass Index (BMI) and understand its interpretation based on age and gender. For adults, BMI is categorized into standard weight statuses. For children and teens, BMI is interpreted using age- and gender-specific percentiles from growth charts.

Unit System: Imperial (lbs, ft/in) Metric (kg, cm)

Weight (lbs):

Height (feet):

Height (inches):

Weight (kg):

Height (cm):

Age (years):

Gender: Male Female

Understanding BMI and Percentiles

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared. For imperial units, the formula is BMI = (weight in lbs × 703) / (height in inches)².

BMI for Adults (Age 20 and Older)

For adults, BMI is used to categorize weight status. These categories are generally consistent regardless of age or gender:

Underweight: BMI less than 18.5
Normal or Healthy Weight: BMI 18.5 to 24.9
Overweight: BMI 25.0 to 29.9
Obesity: BMI 30.0 or greater

While BMI is a useful screening tool, it does not measure body fat directly and should not be used as a diagnostic tool. Factors like muscle mass, bone density, and body composition can influence BMI. Consult a healthcare provider for a comprehensive health assessment.

BMI for Children and Teens (Age 2-19)

For children and teens, BMI is interpreted differently than for adults. Because children's body fatness changes with age and differs between boys and girls, BMI for children is plotted on age- and gender-specific growth charts. These charts show the BMI relative to other children of the same age and sex, expressed as a percentile.

The percentile indicates the relative position of the child's BMI among children of the same age and sex. For example, a child at the 75th percentile has a BMI greater than 75% of children of the same age and sex.

The standard weight status categories for children and teens based on BMI percentiles are:

Underweight: Less than the 5th percentile
Healthy Weight: 5th percentile to less than the 85th percentile
Overweight: 85th percentile to less than the 95th percentile
Obese: Equal to or greater than the 95th percentile

It is crucial to note that this calculator provides an explanation of BMI percentile categories for children and teens. However, a precise percentile calculation requires access to official CDC or WHO growth chart data and should be performed by a healthcare professional who can consider all relevant health factors.

BMI for Infants and Toddlers (Under Age 2)

BMI is not typically used for children under 2 years of age. For this age group, healthcare providers use weight-for-length charts to assess growth and development.

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Underweight: BMI less than the 5th percentile
Healthy Weight: BMI between the 5th and less than the 85th percentile
Overweight: BMI between the 85th and less than the 95th percentile
Obese: BMI equal to or greater than the 95th percentile

" + "Important: This calculator provides an explanation of BMI percentile categories. A precise percentile calculation requires access to official growth chart data and should be performed by a healthcare professional who can consider all relevant health factors."; category = "Interpretation based on age- and gender-specific percentiles"; } else { // Adults (Age >= 20) if (bmi = 18.5 && bmi = 25.0 && bmi = 30.0 category = "Obesity"; } interpretation = "Your calculated BMI is " + bmiRounded + ", which falls into the " + category + " category for adults." + "BMI is a screening tool and not a diagnostic tool. Consult a healthcare provider for a comprehensive health assessment."; } resultDiv.innerHTML = interpretation; } // Initialize unit system display on load window.onload = toggleUnits;