Product barcodes for small brands: what shops expect

4 minute read · updated 2026-11-10

When a shop agrees to stock your product, one of the first things they ask for is a barcode. Making the barcode image is the easy part. The number inside it is what matters, and for most retailers it has to come from one place. This guide explains how it works for small brands, from the first product to the first stockist.

The number comes first

The barcode on a product in a shop is usually an EAN-13: thirteen digits shown as black bars. Those digits are a GTIN, a Global Trade Item Number, and each one identifies one specific product worldwide.

GTINs are issued by GS1, a not-for-profit organisation with an office in most countries. When you join, you get a company prefix, a block of numbers that belongs to your business. You then give one number from that block to each product you sell.

A barcode generator, including Codeshed, turns a number into bars. It can't give you a number that a retailer will accept. That has to come from GS1.

Why not make up a number?

Any thirteen digits with the right check digit will produce a barcode that scans. But a number you invented may already belong to another company's product. When a shop's till looks it up, it might find someone else's item, or nothing. Large retailers check numbers against GS1's registry and won't list products with numbers that aren't registered to the brand.

Barcodes bought cheaply from resellers have a similar problem. They are often numbers originally issued to a different company, so the registry shows that company's name, not yours. Some marketplaces and supermarkets reject them for exactly that reason.

When you need GS1, and when you might not

Supermarkets, chains and big online marketplaces: almost always require GS1 numbers registered to your brand.
Independent shops: many accept GS1 barcodes and some will scan anything, but ask before printing packaging. A shop that later joins a buying group may need proper numbers.
Your own website, market stall or shop: you don't need a retail barcode at all. If you want to scan your own stock, an internal code such as Code 128 or a QR code works and costs nothing. Our guide to asset tags and stock labels covers that.
Books: use an ISBN from your country's ISBN agency, which becomes an EAN-13 starting 978 or 979. See the ISBN barcode page.

One number per variation

Each version of a product a customer can buy needs its own number. A candle in three scents is three products. A T-shirt in four sizes and two colours is eight. A gift set of three candles is another product again, with its own number.

Keep a simple spreadsheet from the start: the number, the product name, size, colour and the date it was assigned. GS1 asks you to record these details, and it saves confusion when you reorder labels a year later. Don't reuse a number for a different product, even after the original is discontinued.

When you sell cartons of several units to wholesalers, the outer box may need its own code, usually an ITF-14. Our guide to which barcode to use explains the difference.

Printing it on packaging

A retail barcode has stricter printing rules than a QR code, because till scanners are less forgiving than phone cameras.

Size. The standard size for an EAN-13 is about 37 mm wide and 26 mm tall, including the numbers. It can be printed between 80% and 200% of that. Shrinking it further, or cutting off the height to save space, is a common reason for rejected packaging.
Colours. Black bars on white is safest. Dark blue or dark green on white also work. Red bars don't, because many scanners use red light and see red as white. Avoid metallic inks and very dark backgrounds.
Quiet zones. Leave clear space on both sides of the bars: at least 11 bar-widths on the left and 7 on the right. Don't let text, borders or folds run into it.
Placement. Put it on a flat area, usually the back or bottom of the pack, away from seams, folds and the edge of curved surfaces like jars.
File format. Send your designer or printer a vector file (SVG or PDF) at 100% size. Scaling a small PNG makes the edges of the bars fuzzy.

Check before you print the run

Print a proof of the actual packaging at actual size.
Scan it with a phone barcode app and check the number matches your spreadsheet exactly.
If possible, scan it at a real till. Many friendly shops will let you try.
For large runs, or if a big retailer asks, GS1 and print suppliers offer verification, which grades how well the barcode is printed.

A short summary

Get your numbers from GS1 if you plan to sell through other retailers. Give each variation its own number and keep a record. Make the barcode at the right size, black on white, with clear margins. Test the printed packaging before ordering thousands. Then you can say yes when the next shop asks for your barcodes.