BMI Calculator
Enter your height and weight to calculate BMI.
Calculate your Body Mass Index (BMI) from height and weight in metric or imperial units. See your BMI score, health category (Underweight, Normal, Overweight, Obese), and a reference BMI chart with your category highlighted. Free, instant, no signup required.
Three steps. No setup.
Drop your content into the field above, or type directly into it. The tool starts working the moment you do — no button to press.
Everything is calculated locally in your browser as you type. No waiting, no uploading, no server involved.
Hit Copy to grab the result, or Download if the tool offers a file. Close the tab — nothing is stored.
Free, private, and built to last.
BMI Calculator is a free online tool that runs entirely in your browser. No data is sent to any server — your input stays private on your device and disappears the moment you close the tab.
It is designed to be fast, simple, and accessible to everyone — whether you are a developer, marketer, student, or business owner. No signup, no ads, no nonsense. Just the tool, ready when you need it.
Frequently Asked Questions
According to the World Health Organisation, a healthy BMI for adults is between 18.5 and 24.9. Below 18.5 is considered underweight; 25.0–29.9 is overweight; 30.0 and above is obese. These ranges apply to adults aged 18–65.
BMI = weight (kg) ÷ height (m)². For example, a person who is 1.75m tall and weighs 70kg has a BMI of 70 ÷ (1.75 × 1.75) = 22.9. In imperial: BMI = (weight in pounds × 703) ÷ height in inches².
BMI applies the same thresholds to men and women, but women naturally carry more body fat than men at the same BMI. Some health organisations suggest that a BMI of 21–23 may be optimal for women, and some use separate thresholds. BMI is a screening tool, not a diagnostic measure.
BMI does not measure body fat directly — it uses height and weight only. It can misclassify muscular people as overweight and older people with low muscle mass as normal weight. It also does not account for where fat is distributed on the body, which affects health risk.
A BMI of 25.0 to 29.9 is classified as overweight. A BMI of 30.0 or above is classified as obese. These thresholds are defined by the World Health Organisation and used in most clinical settings.