Free online tool
Calculate your Body Mass Index (BMI) quickly and understand what your result means. Use centimeters and kilograms, or feet, inches, and pounds.
Enter your height and weight, then select Calculate BMI to see your result.
Your BMI
BMI stands for Body Mass Index. It is a simple screening number that compares adult weight with height. A BMI calculator online like this one uses those two measurements to estimate which adult BMI category a result falls into.
BMI is widely used because it is quick and does not require special equipment. It is not a direct measurement of body fat, muscle, or overall health. Two people can have the same BMI and still have different body composition.
The standard adult formula uses metric units:
BMI = weight (kg) / height² (m²)
If height is entered in centimeters, divide by 100 to convert it to meters. For example, 170 cm is 1.70 m. If weight is 70 kg, BMI is 70 ÷ (1.70 × 1.70), which is about 24.2.
This body mass index calculator can also work as an imperial BMI calculator. Feet, inches, and pounds are converted first, then the same metric formula is used. That keeps metric BMI calculator results and imperial results consistent.
These are the usual adult BMI categories. They are screening ranges, not diagnoses.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Normal weight |
| 25.0–29.9 | Overweight |
| 30.0+ | Obesity |
Use this BMI chart as a quick visual guide to adult ranges. After you calculate BMI, the result card also places a marker on the same scale.
You can calculate BMI without converting units yourself. Choose centimeters or feet/inches for height, and kilograms or pounds for weight.
Metric example: 175 cm and 68 kg. Imperial example: 5 ft 9 in and 150 lb. Switching units converts a value you already typed, so you can move between a metric BMI calculator and an imperial BMI calculator without starting over.
BMI is useful as a general screening measure because it is simple and standardized. It has important limitations:
Treat your result as a starting point, not a verdict. For personalized health advice, consult a qualified healthcare professional.
Adult BMI categories should not be applied in the same way to children or teenagers. Pediatric BMI interpretation generally depends on age and sex.
BMI, or Body Mass Index, is a screening number calculated from height and weight. It is used to place adults into general weight categories. It does not directly measure body fat or diagnose a health condition.
The standard adult formula is BMI = weight in kilograms divided by height in meters squared. If you enter feet, inches, or pounds, this calculator converts those values first, then uses the same formula.
For most adults, a BMI between 18.5 and 24.9 is described as the normal weight range. A useful BMI still depends on age, muscle mass, and other health factors, so it is not a complete definition of health.
The adult BMI formula and the usual adult category ranges are the same for men and women. Body composition can still differ by sex, which is one reason BMI is only a screening measure.
Yes. Choose pounds for weight and feet/inches for height. The calculator converts imperial measurements automatically before calculating BMI.
BMI can overestimate body fat in people with high muscle mass, including some athletes. A high BMI in that situation does not automatically mean high body fat.
This tool uses adult BMI categories. Those categories should not be applied in the same way to children or teenagers. Pediatric BMI interpretation generally depends on age and sex and should be reviewed with a qualified healthcare professional.