Is a QR code a barcode?

What type of barcode is a QR code?

A QR code is a barcode, but a two-dimensional one. It stores data in a grid of squares read in both directions, where a traditional barcode stores it in the widths of bars read across a single line. That difference is why it holds far more in the same area and why a camera can read it at any angle.

The distinction sounds academic until it decides whether your scanner can read your label, or whether the code you generated is the one the system at the other end expects.

One dimension, two dimensions

A linear barcode encodes along one axis. All the information is in the sequence and width of the bars, and the height exists only so the beam has something to hit. You can crop most of the height off and it still reads.

A QR code encodes along two. Position within the grid carries meaning in both directions, which is why it holds hundreds of characters where a linear symbol holds a dozen, and why the three corner squares exist: they tell the reader which way up it is, so rotation stops mattering.

It also carries error correction, which linear barcodes largely do not. A QR code can lose a meaningful share of its area and still decode, and that is what makes it survivable on packaging, on a windscreen, or under a printed logo.

The code on your boarding pass is not a QR code

This is where the confusion costs somebody an afternoon, because people search for a QR generator to reproduce one.

Airline boarding passes generally use PDF417, the wide striped rectangle that looks like a smeared barcode, or Aztec, which is square like a QR code but has a bullseye at its centre instead of three corner squares. Both are 2D symbologies, both hold the same sort of data, and neither is a QR code.

So no QR generator will produce a working boarding pass, and a scanner expecting Aztec will not accept a QR code carrying identical text. The format is part of what the reader is checking. Transport tickets are the same story: Aztec is common on rail because it stays readable when printed small on a thermal ticket.

Which scanners read which

The practical question in a shop or a warehouse, and the answer is about the hardware rather than the code.

A laser scanner sweeps a line and measures what it reflects. It reads linear barcodes and it will never read a QR code, because there is no line to sweep that captures a grid. If a counter has an older laser gun, a QR code on the label is decorative to it.

An imaging scanner takes a photograph and decodes it, so it reads both. Most hardware sold in the last decade is this. Phones are imaging scanners by definition.

If you are labelling for existing equipment, find out which you have before choosing. That question decides the symbology, and our barcode generator covers the linear side, Code 128, Code 39 and GS1-128, when a linear symbol is what the hardware needs.

Choosing between them

Linear where dedicated hardware reads a number off a shelf edge: it is what the equipment is built for and it spends less width per character. QR where the scanner is a phone, where the space is square rather than long, or where scanning should open something rather than type into a field.

Carrying both on one label is common and sensible rather than indecisive, and the sizing consequences of that choice are in QR codes for inventory, where the constraint turns out to be millimetres rather than data.