A barcode is a machine-readable representation of data. In retail and logistics, that data is typically a product identifier—most commonly a GTIN (Global Trade Item Number)—that computers can read faster and more accurately than human-typed entry.
How barcodes work
A barcode encodes numbers (and sometimes letters or URLs) into a pattern of lines, spaces, or dots. A scanner shines light on the pattern, measures the reflections, and converts the result back into the original data. The encoded value is then looked up in a database to retrieve product information such as price, description, or stock level.
Barcodes do not store detailed product data inside the symbol itself. They store an identifier that points to a record in a database. This distinction matters for small business owners choosing their first barcode system: you need both the barcode image and a way to register or share the associated product data with trading partners.
1D barcodes: the classic retail formats
One-dimensional (1D) barcodes—also called linear barcodes—are the familiar patterns of vertical lines seen on nearly every consumer product. The most common formats for retail are:
| Format | Typical use | Digit length | Region |
|---|---|---|---|
| EAN-13 | Retail point-of-sale | 13 digits | Worldwide; standard outside North America |
| UPC-A | Retail point-of-sale | 12 digits | North America |
| ITF-14 | Shipping cartons, cases | 14 digits | Global supply chain |
| GS1-128 | Pallets, logistics, batch/lot data | Variable | Global supply chain |
EAN-13 and UPC-A both encode a GTIN and are functionally interchangeable in most modern scanning systems. An EAN-13 beginning with zero is effectively a 12-digit UPC-A. ITF-14 and GS1-128 are used on outer packaging and logistics units rather than individual consumer items.
For a deeper comparison of when to use each format, see Choosing a barcode type.
2D codes: QR codes and beyond
Two-dimensional (2D) barcodes store data in both horizontal and vertical dimensions, allowing much higher capacity in a smaller space. The best-known example is the QR code, which can encode URLs, contact details, or payment information readable by smartphone cameras.
In supply chain contexts, GS1 Digital Link is a structured way to encode a GTIN within a QR code or Data Matrix symbol. This lets a single code serve multiple purposes: a scanner at checkout reads the GTIN for pricing, while a consumer’s smartphone can follow the embedded URL to product information, sustainability data, or authentication services. GS1 maintains standards for 2D barcode adoption in healthcare, fresh foods, and general retail 1.
What GTINs identify (and what they don’t)
A GTIN identifies a trade item—a product as it is bought or sold. This includes:
- The specific product variant (size, colour, flavour)
- The brand owner who assigned the number
- The packaging level (each, case, pallet)
What a GTIN does not tell you:
| GTIN does NOT indicate | Why it matters |
|---|---|
| Country of manufacture | The prefix does not guarantee origin; it shows where the number was issued 2 |
| Quality or authenticity | GTINs are identifiers, not certifications |
| Who currently owns the brand | Numbers can be transferred or licensed between companies |
This is a common source of confusion. A GTIN beginning with “93” (Australian prefix) does not mean the product was made in Australia—only that the number was originally allocated by GS1 Australia. For more detail, see GTIN overview.
Getting started with barcodes
For small businesses and first-time buyers, the practical steps are:
- Determine how many products need codes — each unique variant needs its own GTIN.
- Choose between GS1 membership or a barcode reseller — GS1 issues numbers directly in most countries; resellers offer numbers from existing pools, often with faster turnaround and lower upfront cost for small catalogues. Both routes produce valid GTINs, though some retailers have specific supplier requirements.
- Select the right barcode format — typically EAN-13 or UPC-A for retail items.
- Generate and test your barcode image — ensure it scans reliably at your intended print size.
You can verify any GTIN’s check digit using the GTIN validator, and check whether a product is already registered in public databases through Barcodes Database.
Further reading
- Choosing a barcode type — match formats to your use case
- GTIN overview — structure, prefixes, and assignment
- GS1 GTIN definition and rules
- GS1 US: What is a GTIN?
- International Barcodes Network — member reseller sites in 120+ countries
Footnotes
-
GS1, “2D Barcodes” — https://www.gs1.org/standards/barcodes/2d-barcodes ↩
-
GS1, “GTIN Management Standard” — https://www.gs1.org/standards/id-keys/gtin ↩