Body mass index for teens age 2–19 — with an honest explanation of what the number actually means at that age.
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Here’s the honest thing to say up front: the adult BMI categories don’t apply to kids and teens. If your 14-year-old comes back with a BMI of 26, that doesn’t mean she’s “overweight” in the adult sense. It means she needs to be plotted on the CDC or WHO growth chart for her age and sex, and interpreted as a percentile.
For anyone aged 2 to 19, the standard framework is: under the 5th percentile = underweight, 5th to 84th = healthy, 85th to 94th = overweight, 95th and above = obesity. The exact BMI number that corresponds to each percentile changes every few months as a kid grows. A BMI of 22 is right in the middle of the healthy range for a 17-year-old girl, but it’s already at the 85th percentile for a 10-year-old girl. Same number, very different meaning.
The calculator above will compute a raw BMI for the height and weight you enter. It’s useful for two things: (1) tracking whether the number is drifting up or down over time, and (2) as a starting point for a conversation with a pediatrician. It is not a substitute for the CDC BMI-for-age percentile chart your doctor uses. If you want the full percentile lookup, that’s a job for the CDC tool at cdc.gov/healthyweight/bmi/calculator.html — they own the growth curves.
Some other things worth knowing about teen BMI: puberty timing matters. A late-blooming 13-year-old can score higher on BMI temporarily because they haven’t had their growth spurt yet — the weight is real, the height hasn’t caught up. Athletes (especially wrestlers, gymnasts, football players) frequently score in the “overweight” band on adult scales because of muscle mass, which is even less meaningful in teens who’ve been training seriously. And body image at this age is fragile — treat BMI as one data point, not a verdict.
If you’re looking for the adult version, use our main BMI calculator, or the men’s and women’s variants. And for a longer take on when to trust BMI and when to ignore it, the BMI guide covers the whole picture.
For adults, BMI uses fixed cutoffs (18.5, 25, 30). For teens (2–19), the CDC uses age-and-sex-adjusted percentile curves. A BMI of 24 might be perfectly healthy for a 17-year-old boy but flagged for a 12-year-old. Always interpret teen BMI as a percentile, not a raw number.
“Normal” for teens is the 5th to 84th percentile on the CDC growth chart for their age and sex. That translates to different BMI numbers at different ages. At 15, a healthy BMI range is roughly 16 to 24 for girls and 16 to 23 for boys — but again, the percentile is what matters, not the number.
No — you’ll get a wrong answer. The adult 18.5–25 healthy range doesn’t map to teen bodies because kids are still growing. The CDC BMI-for-age chart is the correct reference for anyone under 20.
Probably not, though it’s always worth a check-in with a pediatrician. Serious teen athletes routinely score in the 85–95th percentile because of muscle mass. Body composition matters far more than the raw number.
The tripwires are (1) a sudden crossing of major percentile lines in either direction, (2) BMI-for-age above the 95th percentile with signs of metabolic issues (high blood pressure, high blood sugar), or (3) BMI-for-age below the 5th percentile with signs of restrictive eating. In any of those cases, book a pediatrician appointment — a single BMI number isn’t enough context.
We wrote a plain-English guide that covers the history, the limits, and what to actually do about your number.
Read the BMI guide →