BMI Calculator
Calculate your Body Mass Index (BMI), check your BMI category, and estimate a healthy weight range based on your height. Use metric units or imperial units.
BMI is a general screening tool, not a diagnosis. It does not replace advice from a healthcare professional.
Calculate your BMI
Enter your weight and height. The calculator will show your BMI score, category, and estimated healthy weight range.
Your BMI result
Standard adult BMI range
Estimated healthy weight range
What your BMI means
BMI compares weight with height. It is commonly used to screen for weight categories that may be associated with health risks in adults.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 - 24.9 | Normal weight |
| 25.0 - 29.9 | Overweight |
| 30.0 or higher | Obese |
BMI formula
Metric formula: BMI = weight (kg) / height (m)2
Imperial formula: BMI = weight (lb) / height (in)2 × 703
Example: a person weighing 70 kg and measuring 170 cm has a BMI of 24.2.
BMI limitations
BMI is useful because it is simple, but it does not measure body fat directly. Interpret the result with context.
- It may overestimate body fat in athletes or very muscular people.
- It may underestimate risk in people with low muscle mass.
- It does not show where body fat is distributed.
- It is not the only factor used to assess health or fitness.
BMI Calculator FAQ
What is BMI?
BMI, or Body Mass Index, is a simple measure based on weight and height. It is used as a screening tool to estimate whether an adult is underweight, in a normal weight range, overweight, or obese.
What is a healthy BMI?
For most adults, a BMI between 18.5 and 24.9 is commonly considered the normal weight range. A result outside that range does not automatically mean a medical problem, but it may be worth discussing with a professional.
How do I calculate BMI?
In metric units, BMI = weight in kilograms divided by height in meters squared. In imperial units, BMI = weight in pounds divided by height in inches squared, multiplied by 703.
Is BMI accurate?
BMI is helpful for quick screening, but it does not account for muscle mass, bone density, pregnancy, age, or fat distribution. It should not be used as a full health diagnosis.
Does BMI work for children?
Children and teenagers usually need age- and sex-specific BMI percentiles rather than the standard adult BMI categories shown here.