Free BMI Calculator Online
Calculate your Body Mass Index with metric or imperial units
Quick BMI Assessment
Understand your weight status in seconds
Switch freely between kilograms and centimeters or pounds, feet, and inches depending on your preference.
See which WHO-defined BMI category your result falls into: underweight, normal, overweight, or obese.
View the healthy weight range for your specific height so you know your target.
About Our BMI Calculator
Our free BMI calculator uses the standard Body Mass Index formula to give you a quick assessment of your weight relative to your height. It supports both metric and imperial units and shows your WHO weight category along with the healthy weight range for your height.
Frequently Asked Questions
What is BMI?
Body Mass Index (BMI) is a simple measure that uses your height and weight to estimate whether you are at a healthy weight. It is calculated as weight in kilograms divided by height in meters squared.
BMI is widely used by healthcare professionals as a screening tool for weight categories that may lead to health problems.
While useful as a general indicator, BMI does not directly measure body fat and may not be accurate for athletes, elderly people, or pregnant women.
What are the BMI categories?
The World Health Organization defines four main categories: underweight (BMI below 18.5), normal weight (18.5 to 24.9), overweight (25 to 29.9), and obese (30 and above).
These ranges apply to adults aged 20 and older. Different charts are used for children and adolescents.
Being in the normal weight range is generally associated with lower risk of weight-related health conditions.
Is BMI accurate for everyone?
BMI is a useful screening tool but has limitations. It does not distinguish between muscle mass and fat mass, so muscular individuals may have a high BMI despite having low body fat.
Age, sex, ethnicity, and body composition all affect the relationship between BMI and health risk.
For a more complete health assessment, consult a healthcare provider who can consider additional measurements.
How is the healthy weight range calculated?
The healthy weight range is the weight range that corresponds to a BMI between 18.5 and 24.9 for your specific height.
It is calculated by multiplying your height in meters squared by 18.5 and 24.9 respectively.
This gives you a concrete target range in kilograms or pounds depending on your selected unit system.