HEIGHT, WEIGHT & PERSPECTIVE
BMI for every stage.
Explore adult BMI and a proposed height adjustment, or check BMI-for-age percentiles for children and teens.
Your measurements
For adults aged 20+. This is a screening reference, not a diagnosis or a target weight.
YOUR RESULTS
Enter your height and weight to see both results and your standard BMI on the adult scale.
Better BMI for tall people?
Standard body mass index divides weight in kilograms by height in metres squared. Nick Trefethen proposed a different height exponent to address how BMI scales with stature: 1.3 × weight (kg) ÷ height (m)2.5. It produces a lower index than standard BMI above 1.69 m and a higher index below that height. Both match at 1.69 m.
This is a mathematical proposal, not a clinically validated replacement. Trefethen notes that it was not based on epidemiological studies and may not improve assessment. We show both numbers so you can compare the formulas, rather than call one your “true BMI.” Read Trefethen’s explanation ↗
Adult BMI scale
| Standard BMI | CDC category (20+) |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to below 25 | Healthy weight |
| 25 to below 30 | Overweight |
| 30 to below 35 | Obesity (class 1) |
| 35 to below 40 | Obesity (class 2) |
| 40 and above | Obesity (class 3) |
These categories apply to standard BMI only. They are screening categories, not a personal assessment. CDC adult BMI categories ↗
Can children and teenagers use this BMI calculator?
Choose “Child or teen (2–19)” above to calculate an age- and sex-specific BMI percentile. The adult height-adjusted formula is not used for children. You can also use the CDC child and teen BMI calculator.
Does a height adjustment account for muscle or pregnancy?
No. Neither calculation measures body fat or distinguishes muscle, bone and fat mass. Pregnancy also changes how weight should be interpreted. Discuss those circumstances with a healthcare professional rather than using this result to set a weight goal. CDC BMI limitations ↗