Calculate BMI for teenagers 13–19 with CDC age-and-sex-specific percentiles, weight status classification, and growth chart reference data.
The BMI Calculator for Teenagers is specifically designed for adolescents ages 13–19, providing age-and-sex-specific percentile interpretations based on the CDC growth charts. Teenage years bring dramatic physical changes — growth spurts, puberty-driven hormonal shifts, and rapid changes in body composition — that make adult BMI categories completely inappropriate for this age group.
During adolescence, boys typically gain significant muscle mass while girls naturally accumulate more body fat, especially around the hips and thighs. A BMI of 23 might be perfectly healthy for a 17-year-old boy but could be near the overweight range for a 13-year-old girl. This is why the CDC uses sex-and-age-specific percentile charts rather than the fixed adult cutoffs of 25 (overweight) and 30 (obese).
This calculator compares your teen's BMI against CDC reference data for their exact age and sex, providing: the calculated BMI, a percentile rank, weight status classification (Underweight, Healthy, Overweight, or Obese), the healthy weight range at their height, and even a "next year preview" showing how their current BMI would rank at the next age. This helps parents and teens understand whether weight changes represent normal growth or a trend worth discussing with a pediatrician.
Whether you're a parent monitoring your teen's development, a school nurse conducting screenings, or a teenager curious about your own health metrics, this tool provides medically grounded, easy-to-understand results.
Adolescence is a critical window for establishing lifelong health habits. Over 20% of U.S. teenagers are now classified as obese, and early identification allows families to make meaningful lifestyle changes before patterns become entrenched into adulthood.
This calculator makes it easy to check your teen's growth status at home, providing the same percentile-based analysis used by pediatricians. Unlike generic BMI tools, it provides teen-specific context — including how their height compares to the average and a preview of how their current BMI will rank next year.
BMI = (weight in lbs / height in inches²) × 703 The BMI is then compared to CDC growth chart percentile cutpoints for the teen's specific age and sex: - Underweight: < 5th percentile - Healthy Weight: 5th to < 85th percentile - Overweight: 85th to < 95th percentile - Obese: ≥ 95th percentile
Result: BMI 21.3, ~58th percentile — Healthy Weight
A 15-year-old boy at 5'8" and 140 lbs has a BMI of 21.3. The 50th percentile for 15-year-old boys is 20.5, so this teen is near the 58th percentile — well within the Healthy Weight range (5th to 85th percentile).
Puberty typically begins at ages 10–11 for girls and 11–12 for boys, but can start as early as 8 or as late as 14. During this period, dramatic body composition changes make BMI interpretation complex. Boys experience a surge in testosterone that promotes muscle growth and fat loss, which tends to keep BMI in check despite significant weight gain. Girls experience estrogen-driven fat deposition, particularly in the hips, thighs, and breasts, which naturally increases their BMI.
A phenomenon called "adiposity rebound" occurs around age 5–7 when BMI begins to increase after decreasing during early childhood. The timing of this rebound predicts future obesity risk — earlier rebound is associated with higher BMI in adolescence.
The prevalence of obesity among U.S. teenagers has quadrupled since the 1980s, rising from approximately 5% to over 20%. Contributing factors include increased screen time (averaging 7+ hours daily for teens), greater access to calorie-dense processed foods, decreased physical activity, inadequate sleep, and chronic stress. The COVID-19 pandemic accelerated these trends, with studies showing significant weight gain among adolescents during school closures.
The health consequences of teen obesity extend far beyond childhood: obese teens are five times more likely to become obese adults, and they face increased risk of type 2 diabetes, fatty liver disease, sleep apnea, and depression during adolescence itself.
When discussing BMI and weight with teenagers, framing matters enormously. Research shows that parents who focus on health behaviors (balanced eating, enjoying physical activity, adequate sleep) rather than numbers (BMI, weight, calories) raise children with healthier relationships with food and their bodies. Avoid labeling foods as "good" or "bad," don't use weight as a reward or punishment, and model healthy behaviors rather than just prescribing them.
Adult BMI uses fixed cutoffs (18.5, 25, 30) that don't account for the rapid growth and body composition changes during adolescence. A BMI of 26 could be perfectly normal for a 17-year-old athletic boy but would be classified as "overweight" using adult standards.
Yes. Growth spurts can cause temporary BMI fluctuations. Teens who suddenly grow taller may see their BMI drop for a few months until weight catches up. This is normal. Tracking BMI over 6–12 months gives a better picture than any single measurement.
Absolutely. Girls typically gain 15–55 pounds during puberty (ages 10–17), and an increase in body fat is a normal, healthy part of female development. This fat accumulation is necessary for hormone production and reproductive health.
Restrictive diets are not recommended for growing teenagers. Instead, focus on: increasing physical activity, improving food quality (not quantity restriction), reducing sugary drinks and processed foods, getting adequate sleep, and limiting screen time. If your teen's BMI is above the 95th percentile, consult a pediatrician for a supervised plan.
The American Academy of Pediatrics recommends annual BMI-for-age screening at well-child visits. More frequent monitoring (every 3–6 months) may be appropriate if your teen is in the overweight or obese range and is actively working to improve their health.
Yes. Teenage athletes, especially those in strength-focused sports (football, wrestling, gymnastics), may have high BMI due to muscle rather than excess fat. If your athletic teen has a high BMI but visibly low body fat, the percentile may overstate their health risk.