Barcode or QR code, and what converting one into the other really means

Three of the search terms that bring people to this site are some arrangement of the words barcode, QR and convert. It is a fair question with an unsatisfying first answer: there is no conversion, because there is nothing to convert. What there is instead is a value, and two very different ways of drawing it.

A QR code is a barcode

Barcode is the family name. The striped rectangle on a cereal box is a linear or 1D symbology — EAN-13, UPC-A, Code 128, Code 39, ITF-14 — storing data in the widths of bars and spaces along a single axis. QR is a 2D symbology, and so are Data Matrix, PDF417 and Aztec: a grid read in both directions at once, with error correction built in.

The generator on this site offers twelve of them in the same tool, which is the quickest way to see the difference. Put the same twelve digits into EAN-13 and into QR and you get two symbols with nothing visually in common that a scanner will nonetheless read back identically.

”Converting” is re-encoding, not transforming

A symbol is a drawing of a string. Going from one symbology to another means taking that string out of the first drawing and drawing it again in the second, and the practical question is only how you get the string.

From a printed barcode to a QR code. Retail codes print their value underneath in human-readable digits — that is what the row of numbers under an EAN-13 is for. Type those digits into the QR tab of the generator and you have a QR code carrying exactly the same GTIN. No image processing, no upload, and nothing lost.

From a QR code to a barcode. Decode it first: the QR code reader reads an uploaded or pasted image in your browser and shows you the string. Paste that string into the barcode tab and pick a symbology — with one caveat that catches everybody, below.

Note the asymmetry. The reader handles QR codes, not the striped kind, because the human-readable line already solves that direction for the cases that matter.

The caveat: the target symbology has rules

A QR code will hold almost anything. A linear symbology will not, and the constraint is not a preference — the encoding simply cannot express the data:

So a URL in a QR code cannot become an EAN-13, and a 40-character URL that technically fits Code 128 produces a symbol wider than a 100 mm label. This is where most attempts at “converting” a code fall over, and it is worth reading the size and capacity rules before committing to a label size.

The retail rule that decides it for you

If the code is going on something sold in a shop, the symbology is not your choice to make. The number itself is allocated from a GS1 company prefix; an invented one is not yours and may already belong to somebody else’s product. The trade then expects that number in the linear symbology its systems were built around — which is why EAN-13 and UPC-A are still everywhere decades after something denser existed.

GS1’s Sunrise 2027 programme is the industry working to change that, so that checkouts accept 2D codes carrying the same identifier. Its existence is the clearest possible statement about today: a QR code with a GTIN in it is not a substitute for the barcode on the pack, and putting one there in place of the other will fail at the till.

When each one is the right answer

Use a linear barcode for anything read by dedicated hardware: retail checkout, warehouse scanning guns, shipping cases, library and asset labels. They are read reliably at speed, at a distance, by scanners that have done nothing else for thirty years. Inventory work is Code 128’s home ground.

Use a QR code for anything a phone reads: posters, menus, packaging that wants to link to instructions, tickets, Wi-Fi credentials, contact details. Every phone camera detects one natively, it holds a full URL with campaign tags, and its error correction survives being printed on a box that then gets scuffed.

Use both when both audiences exist, which is the honest answer for most packaging. The EAN-13 does the till; a QR code elsewhere on the pack does the customer. They are not competing for the same job, and the space they need is different enough that the layout usually accommodates it — codes on packaging covers where each one sits.

The one-minute version

• A QR code is a barcode; the useful split is 1D versus 2D.
• Converting means re-encoding a value, so first get the value: the digits under the bars, or the reader for a QR code.
• The receiving symbology’s rules decide whether the value can survive the trip.
• For retail, the checkout decides, and today it still wants the linear code.
• For a phone, a QR code wins on capacity, size and native camera support.