BMI Calculator
Calculate your Body Mass Index and see your healthy weight range.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the BMI Calculator
BMI (Body Mass Index) is a quick screening tool that uses height and weight to estimate whether you are at a healthy weight. Here is how to get your result:
- Choose your unit system. Select Imperial for pounds and inches, or Metric for kilograms and meters.
- Enter your weight. Use your current body weight, not your goal weight.
- Enter your height. For imperial, enter total inches (for example, 5 feet 7 inches = 67 inches). For metric, enter height in meters (for example, 1.70).
- Read your result. Your BMI number appears instantly along with your category and the healthy weight range for your height.
Use the Share button to send your inputs to a doctor or trainer, or Copy to paste the result into a health log.
About BMI
BMI is calculated by dividing weight in kilograms by the square of height in meters (kg/m²). For imperial units, the formula uses a conversion factor: (weight in lbs / height in inches²) × 703. The result falls into one of four categories: Underweight (below 18.5), Normal weight (18.5 to 24.9), Overweight (25 to 29.9), and Obese (30 and above).
BMI is a population-level screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, age, or fat distribution. Athletes often have a higher BMI due to muscle mass, while older adults may have a normal BMI despite excess body fat. For a complete picture of your health, consult a physician and consider additional measurements like waist circumference or body fat percentage.
Frequently Asked Questions
What is a healthy BMI range?
A BMI between 18.5 and 24.9 is considered normal or healthy for most adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese. These thresholds apply to adults 20 years and older. Children and teenagers use age- and sex-specific percentile charts instead of fixed cutoffs.
Is BMI accurate for athletes and muscular people?
No. BMI does not distinguish between fat mass and muscle mass. A well-trained athlete can have a BMI in the overweight or obese range while carrying very little body fat. Conversely, someone with a normal BMI can still have an unhealthy amount of body fat if they have low muscle mass. For athletes, body fat percentage measurements are more meaningful than BMI.
How is BMI calculated?
In metric units: BMI = weight (kg) / height (m)². In imperial units: BMI = (weight in lbs / height in inches²) × 703. For example, a person who is 5'7" (67 inches) and weighs 160 lbs has a BMI of (160 / 67²) × 703 = 25.1, which falls in the overweight category.
What is the healthy weight range for my height?
The healthy weight range is the weight at which your BMI falls between 18.5 and 24.9. This calculator shows your personal healthy range automatically. As an example, a person who is 5'7" (67 inches) has a healthy weight range of approximately 118 to 159 lbs. For metric, a person who is 1.75 m tall has a healthy range of approximately 56.6 to 76.3 kg.