BMI chart and range guide
A BMI result is sorted into a range — underweight, healthy weight, overweight, or one of the three obesity classes — to show roughly where it sits among adults of the same height. These ranges are screening references, not diagnoses, and they apply to adults aged 18 and older. The chart below shows each range and what it does, and does not, tell you.
The BMI chart below groups adult results into categories based on height and weight. It can help place a BMI calculator result into a general BMI range, but it does not diagnose health.
On this BMI chart, the numbers mark where each adult BMI range changes, on a scale from 16 to 40+.
BMI uses height and weight. Read more about the BMI formula and why it does not directly measure body fat, muscle, bone, or water.
These BMI categories are intended for adults aged 18 and older. People under 18 should be assessed using age- and sex-specific growth references rather than adult cutoffs. Pregnancy also requires a different clinical assessment.
BMI below 18.5
Weight is low relative to height. Because BMI does not directly measure body fat, it cannot show whether this reflects build, nutrition, or an underlying condition. Interpretation depends on factors BMI leaves out, and one reading is not a diagnosis.
BMI 18.5 – 24.9
Weight sits within the range used as a general reference for adults. Since BMI does not directly measure body fat, a result here does not confirm good health on its own — diet, activity, and medical history all matter, and a single reading is not a diagnosis.
BMI 25.0 – 29.9
Weight is above the general adult reference range for height. BMI does not directly measure body fat, so it cannot separate muscle from fat — a muscular build can place a result here. What it means depends on other health information, and it is not a diagnosis.
BMI 30.0 or higher
This range is grouped into three classes and is associated with higher health risk across populations. That is a general pattern, not a statement about any individual: BMI does not directly measure body fat, interpretation depends on other measures, and a result here is not a diagnosis.
For adults with a BMI of 30 or greater, obesity is often grouped into classes.
Yes. The overweight range starts at 25.0, so a BMI of exactly 25 falls just inside it. A value sitting on a boundary is not meaningfully different from one just below it, and it says nothing on its own about body fat or health.
Class 1 covers 30.0 – 34.9, Class 2 covers 35.0 – 39.9, and Class 3 covers 40.0 or higher. The classes simply subdivide the obesity range; they are not severity diagnoses.
No. These ranges apply only to adults aged 18 and older. People under 18 are assessed with age- and sex-specific growth references, because height and body composition are still changing. Adult cutoffs do not transfer to them.
Yes. BMI uses only height and weight, so it cannot tell muscle from fat. Muscular people can land in the overweight or obesity range while carrying little body fat, which is one reason BMI works better as a screening tool than a verdict. See the BMI questions and answers for more.
This content is for adults 18 years and older and is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.
Use the calculator as a quick starting point, then read your result with context and individual needs in mind.
T9 BMI Check is an educational resource for adults. BMI is a screening tool, not a medical diagnosis, and the information here is general rather than personalized medical advice. We research our content against trusted public-health sources, work to keep it factually accurate, and review it periodically. For guidance about your own health, please consult a qualified healthcare professional.
References
Prepared and maintained by T9 BMI Check
Last reviewed against the cited sources: July 16, 2026
