How to get real product barcodes: GS1 membership and why resold codes are risky
A barcode generator draws bars. It can't give you a product number that retailers will accept. That number, the GTIN, has to come from GS1, the non-profit standards body that runs the retail numbering system in over 100 countries. This guide explains how to get one and what to avoid.
What you're actually buying
When you join GS1 you license a company prefix: a block of digits that identifies your business. You add your own item reference for each product and a check digit, and that makes a GTIN. With an EAN-13, a 9-digit prefix leaves room for 1,000 products and a 10-digit prefix for 100. Some offices, such as GS1 US, also sell single GTINs for businesses with only a few products.
The GTIN, plus the product details you register with it, is what retailers and marketplaces check. The barcode itself is just a way to type the number quickly at a till.
How to get your numbers
- Find your GS1 office. Join GS1 in the country where your business is based. A number from any GS1 office works in every country.
- Choose how many numbers you need. Count every product, size, colour and pack size, then add room for new ones. Prices depend on the country and the size of the block.
- Assign a number to each product. Your company prefix plus an item reference you choose, plus a check digit. Record each one in the GS1 portal with the product's name, brand and image.
- Make and test the barcodes. Draw each number as an EAN-13 or UPC-A, print a sample at the final size and scan it before the print run.
How many numbers do you need?
More than you think. GS1's rules say each distinct trade item needs its own GTIN, so you need a new number for:
- each size, colour, flavour or scent
- each pack size (a single bar, a 4-pack and a case of 24 are three GTINs)
- a change to the declared net quantity, such as 500 g becoming 450 g
- a bundle or multipack sold as one item
Cartons that aren't sold at a till need their own number too, usually printed as an ITF-14 or GS1-128 barcode.
Why not buy cheap codes from a reseller?
Websites that sell UPC codes for a few dollars are usually reselling numbers from company prefixes licensed decades ago, before GS1 required yearly renewal. The prefix is still registered to the original company, not to you. That causes real problems:
- Marketplaces check the GS1 registry. Amazon compares the brand on a listing with the company that owns the GTIN, and may block or remove listings that don't match.
- Retailers reject them. Supermarket chains and large retailers ask for a GS1 certificate or check the registry before taking a new product.
- The number may already be used. Two products with the same number cause wrong prices and stock errors at the till.
- You can't fix the record. Only the licence holder can change what the GS1 registry says about the number.
When you don't need GS1
If the barcode never leaves your business, any number works. Stock labels, asset tags, library cards, event tickets and internal SKUs are best made as Code 128, which holds letters too. Amazon also offers a GTIN exemption for some products without a barcode, such as handmade goods, and books use an ISBN from your national ISBN agency instead (see ISBN barcodes for books).
Once you have your numbers
Make the barcode with the EAN-13 generator or the UPC-A generator; we add the check digit and test-scan it. Then read barcode print size and quiet zone before you send artwork to the printer.