BMI Calculator

The body mass index is the best-known figure for relating body weight to body height. The formula behind it is simple: weight in kilograms divided by height in metres squared. The BMI Calculator takes this arithmetic off your hands and delivers the result the moment you tap Calculate.

What matters is not just the number but its classification. That is why the calculator assigns your BMI directly to one of the eight WHO categories - from severe underweight through normal weight to the three obesity classes. A colour scale with a marker shows you at a glance where your value sits and how far it is from the green normal range. Each category comes with a short, factual note.

The WHO boundaries are firmly set: below 18.5 counts as underweight, 18.5 to 25 as normal weight, 25 to 30 as overweight, and 30 and above as obesity, further split into three classes. These values are internationally uniform and form the basis for most health assessments. The calculator uses exactly these official thresholds.

For all its usefulness, the BMI has clear limits, and the calculator does not stay silent about them. It accounts for neither muscle mass nor age, sex, or build. A well-trained person can land in the overweight range on paper while being perfectly healthy. The BMI is a rough guideline for self-assessment, not a medical verdict - which is why an honest note accompanies every result.

Everything runs entirely in your browser. Your height and weight are sensitive health data, and precisely for that reason they are sent nowhere, stored nowhere, and transmitted to no server. No signup, no account, no tracking. You can feed the calculator as many different values as you like without leaving a trace.

The interface is deliberately plain: two fields, one button, one result. The calculator understands comma-separated values as well as decimal points, and it catches nonsensical input with friendly hints. Anyone who wants to track their BMI over time or combine it with other figures will find further tools in the Werkzeu.ge calculator family.