BMI Calculator – Body Mass Index Chart & Results
Enter height and weight to see your BMI, category, and where you land on a simple scale.
Body Mass Index (BMI) estimates whether your weight is in a typical range for your height. Enter height and weight in imperial or metric units — this BMI calculator shows your number, category, and a simple visual scale.
The formula is weight in kilograms divided by height in meters squared. Imperial inputs are converted first (1 lb ≈ 0.4536 kg; 1 inch = 0.0254 m). Adult categories follow WHO cutoffs: underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (30+).
BMI is a screening tool, not a diagnosis. It does not account for muscle mass or body composition. For pregnancy dating, see the Pregnancy Calculator. Your numbers stay in your browser.
How to use
- Choose imperial (ft/in + lbs) or metric (cm + kg).
- Enter your height and weight.
- Read your BMI, category, and the visual indicator. Results update as you type.
- Use Reset to clear and start over.
Tips
- BMI is a screening number based on height and weight — not a full picture of health. Muscle, bone density, age, and body composition matter too.
- Adult categories here use WHO cutoffs: underweight under 18.5, normal 18.5–24.9, overweight 25–29.9, obese 30+.
- Athletes and people with high muscle mass may score higher without excess body fat.
- Children and teens need age- and sex-specific BMI percentiles — this tool is for adults.
FAQ
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². In imperial units, the calculator converts pounds and inches to metric first, then applies the same formula. Results are shown to one decimal place.
What are the BMI categories?
For adults: Underweight is under 18.5, Normal is 18.5–24.9, Overweight is 25–29.9, and Obese is 30 or higher (WHO adult cutoffs).
Is BMI accurate for everyone?
No. BMI does not measure body fat directly. Very muscular people, older adults, and some ethnic groups may be miscategorized. Treat it as one data point — talk with a clinician for personal advice.
Should I use metric or imperial?
Either works — the math is the same after conversion. Pick the units you know your measurements in.
Can I use this BMI calculator for kids?
Not for clinical decisions. Children and adolescents are assessed with BMI-for-age percentiles. This page uses adult cutoffs only.
Is my data stored?
No. Height and weight stay in your browser. Nothing is sent to a server.