Whether you're numbering a batch of samples, printing inventory labels, or adding a barcode to a cross-border product, the right symbology depends on what you're building. Pick the wrong symbology, miscalculate the check digit, or let the cutter shave off the quiet zones, and your scanner will refuse to read it. This guide walks through each use case so you get the barcode right the first time.
Start With Your Use Case, Then Pick a Symbology
| Symbology | Digits | Best for |
|---|---|---|
| EAN-13 | 13 digits | Retail products and official product barcodes |
| UPC-A | 12 digits | Products sold in North America |
| ITF (Interleaved 2 of 5) | Even number of digits | Logistics cartons and warehouse packaging (high density, wear-resistant) |
For internal management and sample numbering, either ITF or EAN-13 works well. When a product will be sold at retail, choose EAN-13 or UPC-A based on your target market.
The Check Digit: The Silent Reason Barcodes Fail
The check digit is the last digit of the barcode, derived from the preceding digits by a weighted calculation, and used by scanners to catch errors automatically. Type one digit wrong and the barcode becomes invalid. For example, given the first 12 digits 690123456789, the EAN-13 check digit works out to 2, so the complete barcode should be 6901234567892.
The generator supports two foolproof approaches: enter the first 12 digits (EAN-13) or the first 11 digits (UPC-A) and it fills in the check digit automatically, or enter the full number and the tool verifies the last digit, flagging a clear error if it's wrong — so you never print a barcode that turns out unreadable.
Print Specs: Module Width, Bar Height and Quiet Zones
- Module width: start at 2px for print; bars that are too thin blur into a single smear on thermal or low-resolution printers.
- Bar height: very short barcodes are harder to read on some scanners, so give the bars as much height as your label proportions allow.
- Quiet zones: the white space on either side is the scanner's "start zone" — keep at least 10px and make sure label cutting doesn't cut into the bars.
Color and Export
- Use dark bars on a light background; inverted or low-contrast barcodes won't read on some devices.
- For print, use SVG export — vector output scales without losing sharpness; PNG is fine for screens and quick use.
- EAN-13 / UPC-A digits are automatically grouped to the spec (e.g.
6 901234 567892) so the layout matches official retail barcodes.
All of these settings are adjustable right in the Barcode Generator — PNG/SVG are generated locally, nothing is uploaded.
What to Keep in Mind
This tool produces barcodes with a standard, structurally correct encoding — more than enough for testing, inventory, samples and internal management. However, the barcode prefix for products sold at retail must be licensed from organizations such as GS1; don't reuse someone else's product barcode.
Frequently Asked Questions
What is the difference between EAN-13 and UPC-A?
The number of digits and the markets they serve: EAN-13 is 13 digits and is the most common retail barcode worldwide, while UPC-A is 12 digits and is standard in North America.
Is the check digit calculated automatically?
Yes. Enter the first 12 digits (EAN-13) or the first 11 digits (UPC-A) and the check digit is filled in for you; the tool also verifies a manually entered last digit and warns you if it is wrong.
Can I use a generated barcode as an official product barcode?
The encoding structure is correct, but the barcode prefix for products sold at retail must be licensed from organizations such as GS1; this tool is intended for testing, inventory and internal management.
My barcode printed but won't scan — what do I do?
Check whether the module width is too small, whether the left and right quiet zones were trimmed during cutting, and whether there is enough contrast between bar and background; for print, export the SVG vector file.
References
- GS1 barcode standards and applying for product barcodes: https://www.gs1.org/standards/barcodes
- EAN/UPC barcode specifications — GS1: https://www.gs1.org/standards/barcodes/ean-upc