Question 1

Which barcode format should I use?

Accepted Answer

Code 128 is the best default for general use — it encodes any ASCII text compactly and is widely supported by scanners. EAN-13/EAN-8 and UPC-A are retail product codes tied to the GS1 numbering system, Code 39 survives in older industrial systems, and ITF-14 marks shipping cartons.

Question 2

Why is my input rejected for EAN or UPC?

Accepted Answer

Those formats accept only digits at a fixed length: EAN-13 takes 12 digits, UPC-A 11, EAN-8 7 (each plus an optional check digit). If you provide the check digit yourself it must be correct, otherwise enter one digit fewer and the tool computes it for you.

Question 3

What is the check digit?

Accepted Answer

The last digit of EAN, UPC, and ITF-14 codes is calculated from the other digits with a weighted checksum. Scanners use it to catch misreads. The tool appends it automatically when you enter the content without it.

Question 4

Will the generated barcode scan reliably when printed?

Accepted Answer

Yes, if printed with enough size and contrast: keep black bars on a white background, avoid scaling the image non-proportionally, and leave the quiet zone (the white margin) intact. Increase the bar width for low-resolution printers, and prefer the SVG download for crisp print results.

Question 5

Is anything I encode uploaded or tracked?

Accepted Answer

No. Barcodes are rendered entirely inside your browser using a local library; the content never leaves your device, nothing is uploaded or tracked, and the tool works offline once the page has loaded.

Barcode Generator

FAQ