What is BMI and Why Does it Matter?
Body Mass Index (BMI) is a quick way to estimate whether your weight is in a range that’s generally associated with lower health risks. It uses your height and weight to produce a single number that falls into broad categories.
How BMI is calculated
Metric: BMI = weight(kg) ÷ height(m)2
Imperial: BMI = 703 × weight(lb) ÷ height(in)2
Typical adult ranges
- Under 18.5: Underweight
- 18.5 – 24.9: Healthy weight
- 25.0 – 29.9: Overweight
- 30.0 and above: Obesity
These are population guidelines, not personal diagnoses.
When BMI isn’t enough
BMI doesn’t distinguish between muscle and fat, and it doesn’t capture fat distribution. Athletes and older adults can have misleading BMI values. For a fuller picture, doctors may look at waist measurements, body fat percentage, blood tests, and medical history.
Check your BMI
Use the BMI Calculator to get your number in seconds. You can switch between metric and imperial and read simple next steps.
Disclaimer: Information here is educational, not medical advice.