BMI Calculator
BMI Information
Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women.
BMI Categories:
- Underweight = <18.5
- Normal weight = 18.5–24.9
- Overweight = 25–29.9
- Obesity = BMI of 30 or greater
BMI is a screening tool but not a diagnostic of body fatness or health. Consult a healthcare provider for assessment.
BMI Calculator: Understand Your Body Mass Index
Our free BMI calculator helps you determine your Body Mass Index quickly and accurately. Whether you’re tracking your fitness progress, assessing health risks, or planning a weight management program, knowing your BMI is an essential first step.
What is BMI?
Body Mass Index (BMI) is a numerical value calculated from your weight and height that provides a reliable indicator of body fatness for most people. Developed in the mid-19th century by Belgian statistician Adolphe Quetelet, BMI has become the standard health screening tool used by medical professionals worldwide.
How to Calculate BMI
The BMI formula is simple:
- Metric formula: BMI = weight (kg) ÷ height² (m²)
- Imperial formula: BMI = [weight (lb) ÷ height² (in²)] × 703
Our calculator automatically performs these calculations when you enter your measurements, eliminating the need for manual computation.
BMI Categories and What They Mean
The World Health Organization (WHO) defines these standard BMI ranges for adults:
- Underweight: BMI below 18.5
- Normal weight: BMI 18.5-24.9
- Overweight: BMI 25-29.9
- Obesity Class I: BMI 30-34.9
- Obesity Class II: BMI 35-39.9
- Obesity Class III: BMI 40 and above