GS1 company prefix

GS1 is the body that hands out these blocks. It is a membership, renewed yearly, not a one-off purchase.

How the number is built

Your prefix is the front of every GTIN you own. You add your own item numbers after it, and the check digit goes on the end.

A short prefix gives you more item numbers and costs more. A small maker with twenty products does not need the block a supermarket brand needs.

Do you actually need one

Only if you are the brand. If you buy stock from suppliers and resell it, the barcodes are already on the boxes and they belong to whoever made the goods. Use those.

You need your own prefix when you make the product, when you sell it under your own label, or when a retailer or marketplace asks for a barcode you can prove is yours.

Where it goes wrong

Cheap barcodes bought from a reseller. They are real numbers, issued years ago to a company that has since sold them on. They scan, and then a marketplace checks the GS1 registry and finds somebody else’s name against them.

For anything that never leaves your own stockroom, skip all of this. Print Code 128 labels and spend the membership fee on something else.