Step 1: pick the right format
Retail products need EAN-13 or UPC-A; almost everything else uses Code 128. See the barcode types guide if you’re not sure which applies to you.
Step 2: get a valid number, if you need one
If the barcode is going on a retail product, the number has to come from GS1. You can’t make one up. If it’s for internal stock, an asset tag, or anything that isn’t sold through a retailer or marketplace, any consistent numbering scheme you choose yourself is fine.
Step 3: generate the symbol
Enter your number or text into the barcode generator and download it as SVG or PNG. SVG is the better choice for printing since it stays sharp at any size, while PNG drops more easily into a spreadsheet or a listing.
Step 4: test it before printing at scale
Print one, scan it with the device you’ll actually use, and check your print dialog isn’t silently shrinking the page. Most print dialogs scale pages down slightly to fit the printer’s margin without telling you, enough to push a barcode that’s already near its size limit past the point where it scans reliably. Our measured size data tells you roughly where that limit is for each format.