BMI Calculator
Enter your height and weight to find your Body Mass Index and see which category it falls into.
What is BMI?
Body Mass Index (BMI) is a simple calculation using your height and weight to estimate whether you fall within a healthy weight range. It's calculated as weight in kilograms divided by height in metres squared: BMI = weight (kg) ÷ height (m)².
BMI is used widely by health organizations as a quick screening tool because it only requires two easy-to-measure numbers, but it's a general indicator rather than a diagnostic measurement.
BMI categories (adults)
- Below 18.5 — Underweight
- 18.5 – 24.9 — Normal weight
- 25.0 – 29.9 — Overweight
- 30.0 and above — Obese
Common questions (FAQs)
Is BMI accurate for everyone?
BMI is a useful general screening tool but doesn't distinguish between muscle and fat mass, so it can be less accurate for athletes, very muscular individuals, older adults, or during pregnancy. It also doesn't account for body fat distribution.
Does this calculator work for children?
No. BMI for children and teens is calculated and interpreted differently, using age- and sex-specific percentile charts. This calculator is intended for adults.
Is my data stored anywhere?
No — this calculation happens entirely in your browser. Nothing you enter is sent to or stored on a server.
Should I make health decisions based on my BMI result?
No — treat this as a general starting point only. For personalized health guidance, speak with a doctor or qualified healthcare provider. See our Disclaimer for more.
What is a normal BMI for a woman?
The normal BMI range for both adult men and adult women is 18.5 to 24.9. The standard BMI formula does not change based on biological sex for adults.
Can muscles increase my BMI score?
Yes. Heavy muscular development increases total weight, which can push athletes into the 'overweight' or 'obese' category despite very low levels of body fat.
How can I lower my BMI score?
You can lower your BMI by reducing body weight through a combination of regular exercise, nutrition plans, and lifestyle changes guided by medical professionals.
What are the health risks of a high BMI?
A high BMI is statistically correlated with an increased risk of cardiovascular disease, type 2 diabetes, high blood pressure, and certain cancers.
Is a low BMI score dangerous?
Yes. A BMI below 18.5 indicates being underweight, which can be linked to malnutrition, osteopenia, anemia, and reduced immune function.
How is BMI calculated using the Imperial system?
In the imperial system, the formula is: BMI = [Weight (lbs) ÷ Height (inches)²] × 703. This conversion factor accounts for metric scaling.
How often should I calculate my BMI?
Unless you are on a specific weight management plan, calculating your BMI once a month or during routine annual medical checkups is sufficient.
Why doesn't this calculator ask for my age?
For adults (20 years and older), BMI categories are not determined by age. Age is only a direct factor when interpreting BMI percentiles for children.