EV-G06Everyday reference

How BMI is calculated

BMI is one division problem applied to millions of people. Knowing exactly what it measures keeps the result useful and keeps it in its lane.

Open the BMI calculator ↗

One formula, two unit systems

Metric BMI divides weight in kilograms by height in metres squared. The US version multiplies by 703 to correct for pounds and inches.

WEIGHT (kg)÷ HEIGHT (m)²= BMIUS: × 703 with lb / in²

Adult screening ranges

The CDC uses fixed cut-offs for adults 20 and older. Children and teens use age- and sex-specific percentiles instead of these values.

BMI	Screening category
Below 18.5	Underweight
18.5 – 24.9	Healthy weight
25.0 – 29.9	Overweight
30.0 and above	Obesity

A screen, not a diagnosis

BMI cannot separate muscle from fat or say where fat is carried. Muscular builds, age-related muscle loss, and ancestry can shift what a given BMI means for one person.

Boundary: the calculator reports the number and the CDC range it falls in. Interpreting it for your health belongs in a conversation with a clinician.

1 SOURCESource ledger

Check the basis.

01Centers for Disease Control and Prevention — About Body Mass Index ↗

QUESTIONS THIS ANSWERS

Questions this answers

How is BMI calculated?
What are the BMI categories for adults?