What Is a Quick Response (QR) Code?

A Quick Response (QR) Code is a type of barcode that can be read easily by a digital device and which stores information as a series of pixels in a square-shaped grid. QR codes are frequently used to track information about products in a supply chain and often used in marketing and advertising campaigns.

QR codes are considered an advancement from older, uni-dimensional barcodes, and have QR code formats are now standardized under ANSI as well as AIMI in 1997 and to ISO/IEC standards in 2000.

Key Takeaways

  • Quick response (QR) codes are square-shaped matrices of dark or light pixels used to encode and quickly retrieve data using computer devices.
  • An enhancement on traditional barcodes, QR codes can store vastly more information and are used in a variety of applications from supply chain management to cryptocurrency wallet addresses.
  • Several versions and variations of QR codes now exist that are customized to different purposes, or which can store greater amounts of data.

Understanding QR Codes

QR codes were developed in the 1990s as a way to provide more information than a standard barcode. They were invented by Denso Wave, a subsidiary of Toyota, as a way to track automobiles throughout the manufacturing process. Unlike barcodes, which require a beam of light to bounce off of the parallel lines, QR codes can be digitally scanned by devices like mobile phones. They can be generated and read through specialized software.

QR codes consist of black squares arranged in a grid (matrix) on a white background. QR code readers can extract data from the patterns that are present in the QR code matrix. QR codes are able to contain more information than traditional barcodes, and primarily handle four modes of data: alphanumeric, numeric, binary, and Kanji. Despite the increased data capacity, QR codes have not been as popular with consumers as expected. Rather than being created by consumers to share information, they are most commonly associated with advertisers and marketing campaigns.

QR codes have become more widespread in facilitating digital payments and in cryptocurrency systems such as displaying one's Bitcoin address. QR codes are also increasingly used to transmit web addresses to mobile phones. For instance, the QR code shown below encodes the URL for this very entry on Investopedia. Use your phone to give it a try.

QR code encoding this web page's URL
QR code encoding this web page's URL.  Investopedia

QR Codes vs. Barcodes

The amount of information that can be conveyed about a product or service was traditionally limited by the amount of space on the product’s packaging or the advertisement touting its benefits. If a consumer wanted more information about the product – availability, price, attributes – they would have to find a salesperson or request additional documentation.

Barcodes convey data using a combination of various widths of parallel lines and are commonly found on the back of product packages. The lines can be read by machines that have an optical scanner and revolutionized the way that companies managed inventories and pricing. The barcode was first put to practical use in the 1960s by U.S. railroads to track equipment and containers. Traditional, two-dimensional barcodes came into common use in U.S. retail stores in 1974. Barcodes are now found on everything from employee ID badges and hospital bracelets to shipping containers.

Quick Response Code Types

There are a number of QR code types that may be used for different items. For example:

  • Micro QR Code: A smaller version of a traditional QR code used when space is limited. Micro QR codes can vary in size but the smallest is 11 x 11 modules, encoding up to 21 alphanumeric characters.
  • Model 1 QR Codes: Model 1 is the prototype of Model 2 and Micro QR. 1 to 14 versions are registered to the AIMI standard. Its maximum data capacity is 468 bytes, which can encode up to 707 alphanumeric characters.
  • Model 2 QR Codes: Model 2 has an alignment pattern for better position adjustment and contains greater data density than Model 1. 1 to 40 versions are registered to the AIMI standard, with version 40 capable of storing up to 4,296 alphanumeric characters.
  • IQR Code: Can be created in squares or rectangles to be used in where space of shape is an issue. It can be in any one of 61 formats.
  • SQRC: Features a restricted reading function to contain private information.
  • Frame QR: Customizable frame that can contain larger data in formats such as graphics, illustrations, or photos.