Barcode Generator

How Barcode Generator works

Create a scannable Code 39 barcode and download it as PNG. Code 39 handles letters, digits and a few symbols, and scans in every standard barcode reader. Everything happens inside this page: the tool reads your input, runs the calculation or conversion locally, and hands the result back to you. Nothing is transmitted, because there is no backend to transmit it to.

That design choice is deliberate. Most free tool sites upload your files to a server, process them there, and quietly keep a copy. Toolcin cannot do that — the site is a set of static files. If your connection dropped the moment the page finished loading, every tool would still work.

Code 39, character by character

The generator uses Code 39, which encodes each character as nine elements — five bars and four spaces — three of which are wide. That is why the encoded set is limited to digits, uppercase letters and a few symbols.

Each symbol is separated by a narrow gap, and the whole code is wrapped in a start and stop asterisk, which scanners use to find the beginning and end.

What Code 39 can and cannot hold

Digits 0–9, uppercase A–Z, and the symbols space, -, ., $, /, +, % and *. Lowercase letters are not representable — a code with lowercase input has to be upper-cased or a different symbology used.

Code 39 is not self-checking by default, so a smudged bar can read as a different valid code. For inventory where that matters, add a checksum character or use Code 128.

Printing it so it scans

Keep bars sharp — a laser printer at 300 dpi or better. Do not stretch the image horizontally, because the ratio of wide to narrow elements is what the scanner measures. Leave at least 10 times the narrow bar width as a quiet zone on both sides.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions