BMI Calculator

Calculate your body mass index and learn how to interpret this useful starting point for understanding health patterns.

Calculate your BMI

Enter your details below. Choose metric for centimetres and kilograms, or imperial for inches and pounds.

Height (cm)

Weight (kg)

Age

Gender

Unit selection

MetricImperial

Your BMI

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Your BMI category will appear here

Healthy BMI range18.5–24.9

Estimated healthy weight rangeEnter your height to estimate

BMI Range Indicator

UnderweightHealthyOverweightObesity

What this meansBMI is a screening measure, not a diagnosis.

Your measurementsHeight: — · Weight: — · Age: —

What Is BMI?

Body mass index, or BMI, is a screening measure that compares a person’s weight with their height. It can help identify possible weight-related health patterns, but it is not a diagnosis and should be considered alongside other information.

How is BMI calculated?

For metric measurements, BMI is calculated by dividing weight in kilograms by height in metres squared: BMI = weight (kg) ÷ height² (m²). For imperial measurements, the calculation is BMI = 703 × weight (lb) ÷ height² (in²).

BMI Categories and Healthy Ranges

For most adults, the commonly used categories are:

BMI range	Category
Below 18.5	Underweight
18.5–24.9	Healthy weight
25.0–29.9	Overweight
30.0 or higher	Obesity

Healthy range: A BMI from 18.5 to 24.9 is commonly classified as the healthy range for adults, but individual health needs vary.

Limitations of BMI

BMI does not directly measure body fat, muscle mass or fat distribution. It may be less useful for athletes, older adults, pregnant people, children and teenagers, and people from different ethnic backgrounds may have different health risks at the same BMI.