Does not distinguish muscle from fat
A person with substantial muscle mass can have a high BMI without the number describing their health on its own.
Health
BMI Calculator
Calculate body mass index from weight and height, review the adult reference category, and understand the result's limitations.
Main calculation
Calculate your BMI
Enter weight and height. Age, sex, and pregnancy are optional and only adjust the interpretation notes.
Sistema de unidades
kg
cm
lb
years
Publicidad
What your result means
BMI compares weight and height to place a result within adult reference ranges. It is useful as a starting point, but it does not describe body composition, habits, symptoms, or medical history on its own.
Number
Calculated as weight divided by height squared.
Category
The adult category uses reference cutoffs, not an individual diagnosis.
Weight range
Estimated from BMI boundaries of 18.5 and 24.9 for the entered height.
Adult BMI classification
These ranges are shown as a general adult reference. People ages 2 to 19 use BMI-for-age percentiles by age and sex.
| BMI | Category | Visual interpretation |
|---|---|---|
| Below 16.0 | Severe thinness | High alert |
| 16.0–16.9 | Moderate thinness | Alert |
| 17.0–18.4 | Mild thinness | Caution |
| 18.5–24.9 | Healthy range | Normal |
| 25.0–29.9 | Overweight | Caution |
| 30.0–34.9 | Class 1 obesity | Alert |
| 35.0–39.9 | Class 2 obesity | High alert |
| 40.0 or above | Class 3 obesity | High alert |
BMI limitations
Read the result as a screening tool, not a medical conclusion.
Does not measure fat distribution
Abdominal fat can have implications that BMI does not capture.
Does not replace medical assessment
It should be interpreted alongside age, medical history, body composition, waist measurement, and other clinical information.
Special populations need additional context
Pregnancy, childhood, adolescence, and older adulthood require additional criteria.
Results are general estimates based on body mass index. BMI does not directly measure body fat and does not replace a medical assessment. Consult a healthcare professional if you have questions or symptoms, are pregnant, recently experienced weight changes, or have a medical condition.
Calculation example
For an adult who weighs 75 kg and is 172 cm tall, BMI is calculated as follows:
height_m = 172 / 100 = 1.72
BMI = 75 / (1.72 ^ 2)
BMI = 75 / 2.9584
BMI = 25.35Reference sources
Calculation and content are separated so the ranges can be reviewed if editorial criteria change.
Frequently asked questions
How is BMI calculated?
BMI is calculated by dividing weight in kilograms by height in meters squared: weight / height².
What is a healthy BMI for adults?
For adults, the healthy reference range is generally 18.5 to 24.9. It is a general guide, not a diagnosis.
What BMI is considered overweight?
A BMI of 25.0 to 29.9 is classified as overweight in adults. A BMI of 30.0 or higher falls within obesity categories.
Is BMI different for men and women?
The adult formula is the same. Interpretation can still vary with body composition, age, fat distribution, and other health factors.
Why does BMI not always reflect body fat?
Because it does not distinguish muscle, fat, bone, or fat distribution. A muscular person can have a high BMI without necessarily having excess body fat.
Is BMI suitable for children and teenagers?
Children and teenagers use BMI-for-age percentiles by age and sex. This version shows a pediatric note and does not classify those results as adult BMI.
Is BMI suitable during pregnancy?
Current BMI during pregnancy is not an appropriate indicator for evaluating weight. It should be interpreted with professional guidance.
How much should I weigh for my height?
The calculator estimates the weight range associated with an adult BMI of 18.5 to 24.9 for your height. Treat it as a mathematical reference, not a medical target.