Barcode Generator

How to use Barcode Generator

1. Pick the symbology your scanner expects.
2. Enter the data — digits only for EAN and UPC, any ASCII for Code 128.
3. Generate, download, and test-scan a printed copy at real size.
4. EAN-13 and UPC-A include a check digit; an invalid number produces a barcode that fails validation.
5. Leave the quiet zone either side, and never stretch the image out of proportion.
6. Generated in your browser; product data is not transmitted.

The symbologies, and where each belongs

EAN-13 is the global retail standard, thirteen digits including a check digit, and is what a supermarket scanner expects. UPC-A is its twelve-digit North American sibling. Code 128 encodes the full ASCII set at high density and is the workhorse of shipping and warehousing. Code 39 is older and less dense but encodes letters and is still common in industrial and military settings. ITF-14 goes on outer cartons. If you are labelling internal inventory, Code 128 is almost always the right answer.

Retail barcodes need numbers you do not own

An EAN-13 that scans is not an EAN-13 you may use. Retail numbers are allocated through GS1, which issues a company prefix you then extend with your own product codes; the last digit is a check digit computed from the rest. Generating a plausible-looking number and printing it will produce a barcode that scans and collides with somebody else’s product, and retailers will reject it. For internal stock control, where nothing leaves your own system, any scheme you like is fine.

Printing so it actually scans

Keep the quiet zone — the clear margin either side, around ten times the narrow bar width for most symbologies. Do not stretch the image: changing the aspect ratio distorts bar widths, which are the data. Print at a decent resolution; a barcode scaled up from a low-resolution image has fuzzy bar edges that defeat the scanner. Keep it dark on light, avoid glossy laminate that reflects the scanner’s own light back at it, and never print across a fold or a curved seam.