Free BMI Calculator
Calculate your Body Mass Index in metric or imperial units, instantly.
What this does: computes your Body Mass Index from height and weight and shows the matching WHO health category (Underweight, Normal, Overweight, Obese) on a visual gauge. It runs entirely in your browser, is 100% free, and needs no signup.
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Enter your details
UnderweightNormalOverweightObese
Frequently asked questions
Is this BMI calculator free and does it store my data?
Yes, it is completely free with no signup. Every calculation happens locally in your browser using plain JavaScript, and nothing you enter is uploaded, logged, or stored on any server.
What do the BMI categories mean?
This tool uses the WHO adult BMI thresholds: below 18.5 is Underweight, 18.5 to 24.9 is Normal, 25 to 29.9 is Overweight, and 30 or above is Obese. The gauge marker shows exactly where your result falls across these ranges.
Is BMI an accurate measure of health?
BMI is a general screening measure based only on height and weight, so it does not account for muscle mass, bone density, age, or sex. Treat it as a starting point, not a diagnosis, and talk to a healthcare professional for a complete assessment.