Adult BMI calculator with category scale and weight range
Enter adult height and weight in metric or US units. HitEquals reports BMI, the CDC adult category, the weight interval corresponding to BMI 18.5–24.9 at that height and a visual category scale.
Inputs used by this calculator
BMI Calculator uses the fields below. The starting values reproduce the page example; replace them with values from the same units and time period before using the result.
| Input | Starting example | Accepted value | How it is used |
|---|---|---|---|
| Measurement system | US — inches and pounds | US — inches and pounds · Metric — cm and kg | Selects the unit or conversion path used by BMI Calculator. |
| Height (inches or cm) | 69 | 36 to 275 | Supplies the height (inches or cm) quantity used by the published equation or result breakdown. |
| Weight (lb or kg) | 165 | 25 to 1000 | Supplies the weight (lb or kg) quantity used by the published equation or result breakdown. |
What BMI measures
Body mass index relates weight to squared height. It is widely used as an inexpensive screening measure for adult weight categories, but it is not a direct scan of fat, muscle or health.
The CDC adult calculator applies to people age 20 and older. Children and teens require age- and sex-specific percentiles, so this page deliberately does not classify them.
BMI formulas
Metric inputs use kilograms and meters. US customary inputs use pounds and total inches with the conventional factor 703.
BMI=kg/m²BMI=703×lb/in²Worked example
For 75 kg and 175 cm, convert height to 1.75 m. Squaring gives 3.0625; 75 divided by 3.0625 is approximately 24.49, inside the adult healthy-weight category.
- Convert centimeters to meters.
- Square the height.
- Divide kilograms by squared meters.
- Compare the result with adult thresholds.
Adult BMI categories
CDC categories are underweight below 18.5, healthy weight from 18.5 through 24.9, overweight from 25.0 through 29.9 and obesity at 30.0 or above. Obesity is further divided into classes.
Weight range at your height
The displayed range reverses the BMI equation using 18.5 and 24.9. It is mathematical context, not an individual target or treatment recommendation.
weight=BMI×height²Limits of BMI
BMI can differ from measured body composition because it does not distinguish fat from lean tissue. Health history, physical findings and other measures matter. Discuss concerns or major weight changes with a qualified clinician.
CDC adult BMI categories
| Category | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Healthy weight | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Obesity class 1 | 30.0–34.9 |
| Obesity class 2 | 35.0–39.9 |
| Obesity class 3 | 40.0 or greater |
Frequently asked questions
What is BMI?
BMI is weight relative to squared height, used as a screening measure.
What is a healthy adult BMI range?
CDC labels 18.5 through 24.9 as healthy weight for adults.
Does BMI measure body fat?
No. It does not directly measure fat or distinguish it from lean mass.
Can children use this calculator?
No. Ages 2–19 require age- and sex-specific BMI percentiles.
Is the displayed weight range a prescription?
No. It is the weight interval produced by the formula at BMI 18.5–24.9.
What question does this BMI Calculator answer?
Calculate adult body mass index, weight category and the weight range associated with BMI 18.5–24.9.
What to keep in mind
For adults age 20 and older. BMI is a screening measure, not a diagnosis, and does not directly measure body fat or account for every difference in muscle, age, pregnancy or body composition.
Results are rounded for display in US format, with money in dollars and cents; CSV exports keep full calculation precision. This is a calculation summary, not an official certificate.