Barcode generator

Which barcode do you need?

The barcode type follows from where it will be scanned. Store checkouts read the GS1 retail barcodes (UPC and EAN), which hold only digits. Warehouses, offices and repair shops scan their own labels, where Code 128 is the usual choice.

Each format has its own page with more detail: the UPC barcode generator, the EAN-13 barcode generator (including ISBN book barcodes) and the Code 128 barcode generator.

Where UPC and EAN numbers come from

A retail barcode is only as good as the number inside it. UPC and EAN numbers are GTINs (Global Trade Item Numbers), and each one is made of a GS1 company prefix, an item number the company chooses, and a check digit. GS1 is the nonprofit standards body that licenses those prefixes; in the United States that's GS1 US, which also offers single numbers for businesses with only a few products. Prices and options change, so check them on GS1 US's own site.

This generator draws the barcode for a number you already have. It doesn't issue numbers, and it can't tell whether a number is registered to you. Be wary of very cheap numbers resold online: GS1's records still name the company that first licensed them, which can cause trouble with retailers and marketplaces that check.

How the check digit works

The last digit of every UPC and EAN is a check digit, so a scanner can tell when it has misread a bar. Take the UPC 03600029145: starting from the right, the digits in alternate positions add up to 14, and three times that is 42. The other digits add up to 16, for a total of 58. The next multiple of ten is 60, so the check digit is 2 and the full number is 036000291452. Type a full number into the generator and it checks the last digit the same way; a mismatch nearly always means a typo.

Getting it to scan

• Keep the size in range. UPC and EAN barcodes can be printed from 80% to 200% of the standard size. Code 128 and Code 39 have no fixed size, but bars thinner than about 7.5 mil (0.19 mm) need a sharp printer.
• Leave the quiet zones blank. The empty space at each end tells the scanner where the barcode starts and stops. The downloads include it; don't crop it off or print text in it.
• Use dark bars on a light background. Most scanners light the code with red light, so red, orange and yellow bars all but disappear. Black or dark blue on white is safest.
• Match the printer. Pick 203 or 300 DPI to match a thermal label printer, or 300 to 600 DPI for office and commercial printing, and place the image at 100% rather than stretching it.
• Test before a print run. Scan a printed sample with the scanner that will be used, or at least a phone app. This page can't certify that a barcode will pass a retailer's verification.

Making many barcodes at once

Choose A batch from a list, paste up to 500 values (one per line, straight from a spreadsheet column) and the generator checks each one. Lines with problems are listed with the reason, and you can remove them in one click. Every barcode in the ZIP is named after its value, so 012345678905.png is the barcode for 012345678905.

Pricing those products? Work out a selling price from your cost with the markup calculator, check what you keep with the margin calculator, and plan a sale with the discount calculator.