Free BMI Calculator
Calculate your Body Mass Index instantly, see your BMI category and healthy weight range, and keep a private calculation history on your device.
BMI Scale
BMI Guide
What is BMI?
Body Mass Index (BMI) is a simple calculation that compares an adult's weight with height. It is commonly used as a screening measure to place adults into broad weight categories.
How is BMI calculated?
For metric measurements, BMI is calculated by dividing weight in kilograms by height in metres squared. For imperial measurements, the calculator converts the entered values before applying the same BMI concept.
What is a healthy weight range?
For adults, this calculator uses the commonly used BMI range of 18.5–24.9 to estimate a corresponding weight range for the entered height. This is an estimate, not a personal medical target.
Does BMI tell the whole story?
No. BMI does not directly measure body fat or body composition and can be less informative for some people, including highly muscular individuals. It should be interpreted alongside other health information.
BMI Categories
Underweight
Below 18.5BMI below the commonly used healthy range.
Healthy Weight
18.5–24.9BMI within the commonly used healthy range.
Overweight
25.0–29.9BMI above the commonly used healthy range.
Obesity
30.0 or higherBMI in the obesity range.
Calculation History
History is stored only in this browser using local storage.
Frequently Asked Questions
What is a healthy BMI?
For most adults, a BMI from 18.5 to 24.9 is commonly classified as the healthy-weight range.
Is BMI accurate for everyone?
No. BMI is a screening measure and does not directly measure body fat or body composition. It may not accurately reflect health status for everyone.
Can I use pounds and feet?
Yes. Select Imperial and enter your weight in pounds and height in feet and inches.
Is this calculator free?
Yes. The calculator is free to use. No account is required, and calculation history is stored locally in your browser.
Does age or sex change adult BMI?
The standard adult BMI formula itself does not change by age or sex. For children and teenagers, BMI must be interpreted using age- and sex-specific growth charts rather than adult BMI categories.