BMI for Men, Women, Children and Older Adults
Does BMI change with sex or age? How BMI is read for adult men and women, children, teens and older adults.
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Frequently asked questions
Is BMI different for men and women?
For adults, the formula and category cut-offs are the same for both. Sex mainly affects how the number is interpreted, not the scale.
How is BMI assessed for children?
By plotting it on age- and sex-specific percentile charts rather than adult categories, because healthy ranges change during growth.
Why do women and men with the same BMI differ?
On average women carry more body fat at a given BMI, since BMI measures only height and weight, not composition.
Does BMI change with age?
The number can, and its interpretation does too, as muscle mass tends to decline with age. Older adults may be assessed with extra context.
Should I use adult BMI categories for a teenager?
No. Use the age- and sex-specific percentile charts designed for children and teens instead.
Is BMI a diagnosis?
No. It is a general screening tool best interpreted by a healthcare professional alongside other measures.
Does BMI differ by sex and age?
For adults, BMI uses the same formula and the same category cut-offs for men and women — there is no separate "male" or "female" BMI scale. Where sex and age matter most is in interpreting the number, and in how BMI is assessed for children and teenagers.
Children and teens
For under-20s, a raw BMI number is not compared with adult bands. Instead it is plotted on age- and sex-specific percentile charts (such as the CDC growth charts), because healthy body composition changes a lot during growth and differs between boys and girls at each age.
Why interpretation varies
At the same BMI, women on average carry more body fat than men, and body composition shifts with age as muscle is gradually lost. So two people with an identical BMI can have different proportions of muscle and fat, which is why context matters.
BMI is a general screening measure, not a personal diagnosis. A healthcare professional can interpret it appropriately for your age, sex and circumstances, alongside other indicators of health.
Results are estimates for general guidance in United States and may not reflect the latest local rates, fees or rules. Check official sources before making decisions.