How is BMI calculated?

In metric units, BMI = weight (kg) ÷ height (m)². In imperial units, BMI = 703 × weight (lb) ÷ height (in)². Both formulas give the same result for the same body.

What do the BMI categories mean?

Under 18.5 is classified as underweight, 18.5–24.9 as normal weight, 25.0–29.9 as overweight, and 30.0 and above as obese, per the World Health Organization's standard adult BMI ranges.

Is BMI an accurate measure of health?

BMI is a quick screening tool based only on height and weight — it doesn't account for muscle mass, bone density, age, sex, or fat distribution, so it can misclassify very muscular or very lean people. It's a starting point, not a diagnosis; talk to a doctor for a fuller picture.

Is my data sent anywhere?

No. The calculation happens locally in your browser and nothing you enter is transmitted or stored.

BMI CALCULATOR

Enter your height and weight to get your Body Mass Index and category. Nothing leaves your browser.

Height (cm)

Weight (kg)

Your BMI22.9Normal weight

BMI range	Category
Below 18.5	Underweight
18.5 – 24.9	Normal weight
25.0 – 29.9	Overweight
30.0 and above	Obese

How to calculate your BMI

1
Choose metric (cm / kg) or imperial (ft, in / lb) units.
2
Enter your height and weight.
3
Read your BMI and category instantly — it updates as you type.

Questions

How is BMI calculated?: In metric units, BMI = weight (kg) ÷ height (m)². In imperial units, BMI = 703 × weight (lb) ÷ height (in)². Both formulas give the same result for the same body.
What do the BMI categories mean?: Under 18.5 is classified as underweight, 18.5–24.9 as normal weight, 25.0–29.9 as overweight, and 30.0 and above as obese, per the World Health Organization's standard adult BMI ranges.
Is BMI an accurate measure of health?: BMI is a quick screening tool based only on height and weight — it doesn't account for muscle mass, bone density, age, sex, or fat distribution, so it can misclassify very muscular or very lean people. It's a starting point, not a diagnosis; talk to a doctor for a fuller picture.
Is my data sent anywhere?: No. The calculation happens locally in your browser and nothing you enter is transmitted or stored.