A QR code (short for "quick response" code) is a type of barcode that contains a matrix of dots. It can be scanned using a QR scanner or a smartphone with built-in camera. Once scanned, software on the device converts the dots within the code into numbers or a string of characters. For example, scanning a QR code with your phone might open a URL in your phone's web browser.
All QR codes have a square shape and include three square outlines in the bottom-left, top-left, and top-right corners. These square outlines define the orientation of the code. The dots within the QR code contain format and version information as well as the content itself. QR codes also include a certain level of error correction, defined as L, M, Q, or H. A low amount of error correction (L) allows the QR code to contain more content, while higher error correction (H) makes the code easier to scan.
QR codes have two significant benefits over traditional UPCs – the barcodes commonly used in retail packaging. First, since QR codes are two-dimensional, they can contain significantly more data than a one-dimensional UPC. While a UPC may include up to 25 different characters, a 33x33 (version 4) QR code, can contain 640 bits or 114 alphanumeric characters. A 177x177 (version 40) QR code can store up to 23,648 bits or 4,296 characters.
Another advantage of QR codes is that they can be scanned from a screen. Standard UPC scanners use a laser to scan barcodes, which means they typically cannot scan a UPC from a screen (like a smartphone). QR scanners, however, are designed to capture 2D images printed on paper or displayed on a screen. This makes it possible to use a QR code on your smartphone as a boarding pass at the airport or as a ticket for an event.