What is a BMI calculator?

A BMI calculator is a tool that calculates your Body Mass Index using your height and weight. BMI is used as a general screening measure to classify weight status in adults.

How is BMI calculated?

BMI is calculated by dividing weight by height squared. Metric formula: weight in kilograms divided by height in metres squared. Imperial formula: 703 multiplied by weight in pounds divided by height in inches squared.

What is a healthy BMI range?

For most adults, a healthy BMI range is between 18.5 and 24.9. Values below or above this range may indicate underweight or overweight status.

Is BMI an accurate measure of health?

BMI is a useful screening tool but does not directly measure body fat or overall health. Factors such as muscle mass, age, and body composition can affect BMI interpretation.

Can BMI be used for everyone?

BMI is intended for adults aged 18 and over. It may not be suitable for children, athletes, older adults, or pregnant individuals without additional context.

Is this BMI calculator free to use?

Yes. This BMI calculator is free to use and provides instant results based on the information you enter.

Free Online BMI Calculator.

Use this BMI calculator to calculate your Body Mass Index (BMI) based on your height and weight. The calculator supports both metric (kg, cm) and imperial (lb, ft/in) units and displays your BMI along with the corresponding category.

BMI is a commonly used screening tool that helps adults determine whether their weight is within a healthy range for their height..

Use Our BMI Calculator Below

Use this BMI calculator to estimate your Body Mass Index based on your height and weight. Choose metric or imperial units to calculate your BMI and see the corresponding BMI category.

BMI Calculator

Weight (kg)

Height (cm)

Your BMI

—

BMI categories (adults)

Underweight < 18.5

Healthy weight 18.5–24.9

Overweight 25.0–29.9

Obesity 30.0+

What Is BMI?

BMI (Body Mass Index) is a numerical value calculated from a person’s weight and height. It is used as a general indicator to classify weight status in adults.

BMI is calculated using one of the following formulas:

Metric: weight (kg) ÷ height² (m²)
Imperial: 703 × weight (lb) ÷ height² (in²)

The result places you into a BMI category such as underweight, healthy weight, overweight, or obesity.

BMI Categories for Adults

BMI categories are commonly defined as:

Underweight: below 18.5
Healthy weight: 18.5 to 24.9
Overweight: 25.0 to 29.9
Obesity: 30.0 and above

These ranges apply to most adults aged 18 and over.

How to Use the BMI Calculator

To calculate your BMI:

Choose Metric or Imperial units
Enter your weight and height
View your BMI result instantly
See your BMI category highlighted on the scale

The calculator updates automatically when you change any value.

What Does Your BMI Result Mean?

Your BMI result provides a general indication of whether your weight is proportionate to your height. It is widely used in population health studies and by healthcare professionals as a screening measure.

However, BMI does not directly measure body fat or overall health.

Limitations of BMI

While BMI is useful, it has some limitations:

It does not account for muscle mass
It may not accurately reflect health for athletes
It does not consider age, sex, or body composition
It should not be used as a medical diagnosis

BMI should be considered alongside other health indicators.

Important Disclaimer

This BMI calculator is provided for informational purposes only. It is not a medical tool and should not be used to diagnose health conditions. For personalised health advice, consult a qualified healthcare professional.