Result
This page has no server side at all. The table you paste is parsed by JavaScript inside your own browser, the chart is drawn on a canvas element on your machine, and the export file is assembled locally. Nothing is uploaded, stored or written to any log. You can disconnect from the network after the page has loaded and everything will still work — which is the simplest way to verify the claim yourself.
Facts and limits of this method
| Exact ratio | 1 inch = 2.54 centimeters exactly |
|---|---|
| Reverse ratio | 1 centimeter ≈ 0.3937008 inches |
| Standard | The international yard and pound agreement of 1959 |
When it misleads you
- The ratio 1 inch = 2.54 cm is exact, set by international agreement in 1959, not an approximation; historical pre-war British or American inches could rarely differ at the sixth or seventh decimal place.
- Rounding is applied only to the displayed result — internal calculations use the full precision of JavaScript floating-point numbers.
- The converter works with linear dimensions (length), not area — to convert square inches to square centimeters, the factor must be squared (2.54² = 6.4516).
How it is calculated
If the source unit is inches, the entered value is multiplied by 2.54 to give length in centimeters.
If the source unit is already centimeters, the value is used unchanged at this step.
If the target unit is inches, the centimeter value is divided by 2.54.
The result is rounded to the chosen number of decimal places and updates instantly whenever any parameter changes.
Questions and answers
Why 2.54 specifically, rather than a round number?
Because the inch and centimeter historically developed in different measurement systems (imperial and metric); in 1959 the inch was officially defined as exactly 2.54 cm to eliminate discrepancies between national standards.
Can I use this for a TV or monitor screen?
Yes, screen diagonals are often given in inches — the converter helps translate them to centimeters for comparison with familiar metric sizes.
Does it work for area (square inches)?
Not directly — for area, the 2.54 factor needs to be squared (giving 6.4516); use a separate area converter for that.
Is my data sent anywhere?
No, the whole calculation runs in your browser.