QR code

A QR code is a two-dimensional matrix barcode. It was developed in 1994 at Denso Wave, then a division of Denso Corporation, in Japan. Its original purpose was the high-speed tracking of automotive parts during manufacturing. The name is an abbreviation of Quick Response, a phrase chosen to reflect the emphasis on high-speed reading.

The code was invented by Masahiro Hara and a two-person team at Denso Wave. It is patented by Denso Wave, but the company has not exercised its rights, leaving the code free to use.

The QR code is a two-dimensional matrix barcode, and its origins lie in the factory floor rather than the consumer market. Its original purpose was the high-speed tracking of automotive parts during manufacturing, a task for which the linear barcodes of the day were poorly suited. In 1992, manufacturing sites asked Masahiro Hara — then working on barcode scanners and OCR devices at Denso — for scanners that could read codes faster, which set the QR code project in motion. The difficulty was concrete: because each barcode holds only about 20 characters, factory workers sometimes had to scan around 1,000 barcodes a day, which made the work less efficient than intended.

A team led by Masahiro Hara at Denso Wave set out to track car-manufacturing parts more effectively and developed the square two-dimensional code released in 1994 as the QR code. The inventor is recorded as Masahiro Hara and a two-person team at Denso Wave, and the team that developed the QR code was indeed tiny: Masahiro Hara led a two-person team. The code was developed in 1994, at Denso Wave (then a division of Denso Corporation), Japan. Britannica notes the QR code was developed in 1994 by Denso Wave — a Denso division under Toyota Motor Corporation — to track automobile parts during assembly. Denso Wave announced the release of the QR Code in 1994; the letters QR stand for “quick response”, reflecting the focus on high-speed reading.

The design brief was to ease barcode reading for Denso's manufacturing staff, to carry large amounts of information efficiently, and to be used freely by people everywhere. After a year and a half of trial and error, the team finished a code that could carry about 7,000 numerals, plus kanji characters, and be read more than ten times faster than other codes. The QR code lets scanners find and interpret its information 20 times faster than earlier matrix codes, opening countless possibilities for linking physical and digital life. Denso Wave lists the QR code's main features as high data capacity, small print size, kanji and kana support, resistance to dirt and damage, 360° readability and the structured append feature.

Denso Wave published the QR Code specifications so anyone could use them freely, and though it retained the patent rights it declared it would not exercise them — a decision that helped the code spread worldwide. The code was patented by Denso Wave, with rights not exercised, leaving it free to use. Denso Wave holds several QR code patents but exercises them only in a limited way, waiving its rights to a key patent for standardized codes to encourage widespread use. “QR Code” is a registered trademark of Denso Wave Incorporated.

Smaller variants followed the original code: the Micro QR Code, made a Japanese (JIS) standard in 2004, and the iQR Code with rectangular modules in 2008. Denso Wave also created the Micro QR Code for tracking small objects; it comes in four versions from 11×11 to 17×17 modules. The smallest variant, the Micro QR Code, spans 11×11 to 17×17 modules and holds up to 35 numerals. Micro QR Code needs only one orientation-detection pattern and a margin as narrow as two modules, and its largest version (M4, 17×17 modules) stores up to 35 numerals.

A rectangular variant, the rMQR Code (ISO/IEC 23941:2022), holds up to 361 numerals in as little as 7×43 modules. The rectangular rMQR Code was designed for narrow spaces where the conventional QR code cannot be printed, and holds more data than Micro QR Code. ISO/IEC 18004 is the international standard that defines the QR code symbology: its characteristics, encoding methods, symbol formats, error-correction rules and reference decoding algorithm. Under the standard, the largest QR code (Version 40) is a 177×177 matrix that can hold 7,089 numeric or 4,296 alphanumeric characters, while the smallest (Version 1) is 21×21.

QR code use took off among the Japanese public in 2002, when mobile phones with a built-in QR code reader went on sale. In 2014 the QR code development team received the European Inventor Award's Popular Prize, chosen by public vote among the finalists. According to Britannica, Masahiro Hara was inspired to create the QR code while playing go, the Japanese board game of black and white stones on a grid. Apple's iPhones can scan QR codes with the built-in Camera app or Code Scanner, without installing anything extra.

Looking ahead, GS1's Ambition 2027 sets an initial goal that retail point-of-sale scanners worldwide can read and process both old linear and new 2D barcodes by the end of 2027. The retail transition is framed as GS1 Ambition 2027: retail POS scanners to read 2D barcodes by end of 2027.

The QR code is a two-dimensional matrix barcode, a form defined by its arrangement of data in two dimensions rather than the single line of an ordinary barcode ^{1QR Code · Encyclopædia Britannica ↗}. Its name abbreviates Quick Response, a reference to the high-speed reading the design was intended to make possible ^{2History of QR Code · DENSO WAVE INCORPORATED (QRcode.com) ↗}. The symbology is specified in forty symbol versions, numbered from 1 to 40, each with a different number of modules ^{14Information capacity and versions of QR Code · DENSO WAVE INCORPORATED (QRcode.com) ↗}. The smallest symbol, Version 1, is a 21×21 grid, while the largest, Version 40, is 177×177, with every successive version adding four modules per side ^{14Information capacity and versions of QR Code · DENSO WAVE INCORPORATED (QRcode.com) ↗}.

Capacity scales with the symbol version. At the top of the range, Version 40 can hold 7,089 numeric characters, 4,296 alphanumeric characters, 2,953 binary characters or 1,817 kanji characters ^{8DENSO WAVE Develops “rMQR Code”, a new rectangular QR Code that can even be printed in long, narrow spaces (news release) · DENSO WAVE INCORPORATED ↗}. Four standard encoding modes are used across the symbology: numeric, alphanumeric, byte/binary and kanji ^{7QR code · Wikipedia ↗}. Error correction allows the data to be restored if the symbol becomes dirty or damaged, and it is selectable across four levels ^{15Error correction feature · DENSO WAVE INCORPORATED (QRcode.com) ↗}. These levels are designated L, M, Q and H, corresponding to recovery capacities of approximately 7 percent, 15 percent, 25 percent and 30 percent respectively ^{8DENSO WAVE Develops “rMQR Code”, a new rectangular QR Code that can even be printed in long, narrow spaces (news release) · DENSO WAVE INCORPORATED ↗}.

Reading depends on three position-detection patterns, which allow the code to be scanned quickly from any angle ^{1QR Code · Encyclopædia Britannica ↗}. These patterns sit in three corners of every QR code ^{4Masahiro Hara, Motoaki Watabe, Tadao Nojiri, Takayuki Nagaya, Yuji Uchiyama — European Inventor Award (Popular Prize 2014) · European Patent Office (EPO) ↗}. The international standard governing the symbology is ISO/IEC 18004, first published in 2000, whose fourth edition dates to 2024 ^{16ISO/IEC 18004:2024 — QR code bar code symbology specification · International Electrotechnical Commission (IEC) Webstore ↗}. A rectangular variant, the rMQR Code, is specified under ISO/IEC 23941:2022 and can carry up to 361 numerals in a footprint as small as 7×43 modules ^{8DENSO WAVE Develops “rMQR Code”, a new rectangular QR Code that can even be printed in long, narrow spaces (news release) · DENSO WAVE INCORPORATED ↗}.

A QR code is a two-dimensional matrix barcode whose design includes an error-correction capability, allowing the original data to be restored if the symbol becomes dirty or damaged. Four selectable levels are defined, labelled L, M, Q and H, corresponding to progressively greater tolerance. The scheme rests on the Reed–Solomon code, which was originally developed against noise in satellite and space-probe communications and which corrects errors at the byte level. Because of this, even a code that is partially smeared or damaged can yield its original data.

The choice of level is a practical one. Factories where codes are exposed to dirt often adopt the higher Q or H levels, while clean environments handling large amounts of data can afford the lighter L level. Level M is the most commonly chosen. The distinction matters most where conventional markings fail: unlike stained barcodes, a QR code with error correction can still be read accurately even when part of it is stained or missing.

Error correction is not an optional accessory but part of the symbology itself. The international standard ISO/IEC 18004 defines the QR code's characteristics, encoding methods, symbol formats, error-correction rules and reference decoding algorithm. The current edition, ISO/IEC 18004:2024, is the fourth edition, published in August 2024, and carries the formal title “QR code bar code symbology specification”. Denso Wave lists resistance to dirt and damage among the code's main features, alongside high data capacity, small print size, kanji and kana support, 360° readability and the structured append feature.

The smallest member of the family is the Micro QR Code, a variant created for tracking small objects. It comes in four versions spanning 11×11 to 17×17 modules, and its largest version stores up to 35 numerals. Where a full QR code relies on three position-detection patterns, the Micro QR Code needs only one orientation-detection pattern, together with a margin as narrow as two modules. These reductions make the symbol practical where space is at a premium.

The rectangular rMQR Code was designed for narrow spaces in which the conventional QR code cannot be printed, and it holds more data than the Micro QR Code. It can be printed in long, narrow spaces while keeping the scan speed and data capacity of the QR code. In as little as 7×43 modules it stores up to 361 numerals. The variant is specified as ISO/IEC 23941:2022 and received ISO certification, so it can be used freely around the world, like the original QR code.

The QR code is a two-dimensional matrix barcode whose technical definition rests on an international standard. ISO/IEC 18004 is the international standard that defines the QR code symbology: its characteristics, encoding methods, symbol formats, error-correction rules and reference decoding algorithm. The current edition of the standard, ISO/IEC 18004:2024 (the fourth edition, published in August 2024), carries the formal title “QR code bar code symbology specification”. The standard was first published in 2000.

The code itself is patented by Denso Wave, yet its rights are not exercised, leaving it free to use. Denso Wave published the QR Code specifications so anyone could use them freely, and though it retained the patent rights it declared it would not exercise them — a decision that helped the code spread worldwide. Denso Wave holds several QR code patents but exercises them only in a limited way, waiving its rights to a key patent for standardized codes to encourage widespread use. The name itself remains protected: “QR Code” is a registered trademark of Denso Wave Incorporated.

The QR code is a two-dimensional matrix barcode, and its spread followed the tools that could read it. Use took off among the Japanese public in 2002, when mobile phones with a built-in QR code reader went on sale. The code stores up to around 7,000 characters and is now used worldwide, especially as a key technology for cashless payment. Scanning is now native to the devices most people already carry: the code is built into iPhone (iOS 11+) and Android camera apps. Android and iOS devices (since iOS 11) can scan QR codes natively, after a period when third-party scanner apps were required.

QR codes date from the 1990s, but in the UK they truly came to prominence during the COVID lockdowns, from ordering food to proving vaccination status. After the pandemic broke out, many pubs and restaurants quickly installed QR code systems for menus, ordering and payment. The BBC described QR codes as a technology from the 1990s that proved extremely useful in the Covid era, from menus to payments. A US restaurant co-founder told the BBC that five years of future technology adoption was compressed into five months during the pandemic.

Retail scanning is moving toward two-dimensional symbologies under GS1's Ambition 2027, an initial goal that point-of-sale scanners worldwide be able to read and process both old linear and new 2D barcodes by the end of 2027. A QR code with GS1 Digital Link extends product packaging into an online gateway to information such as ingredients, allergens, nutrition and sustainability details. The demand behind such richer codes comes from consumers, brands, retailers and regulators alike, all of whom want to know more about products and to gain access to more information from packaging. The distinction matters because traditional barcodes are usually scanned by companies for supply-chain systems, while QR codes are usually scanned by consumers to open a product-information webpage.

QR codes are increasingly used for touchless payments, where EMV QR Code technology lets merchants offer many payment options with a single code at checkout. The EMV QR Code Specifications consist of two specifications covering the two types of QR payment: consumer-presented mode and merchant-presented mode. In merchant-presented mode, the merchant displays the QR code and the consumer scans it with a mobile device. The QR code's capacity of up to around 7,000 characters has helped make it a key technology for cashless payment worldwide.

The QR code's convenience has a darker side. Criminals increasingly embed QR codes in phishing emails — a technique sometimes called “quishing” ^{17QR Codes - what's the real risk? · UK National Cyber Security Centre (NCSC) ↗}. Not all phishing-detection tools scan images, so a QR code pointing to a malicious site can slip through email defences ^{17QR Codes - what's the real risk? · UK National Cyber Security Centre (NCSC) ↗}. The FBI's 2022 alert warned that criminals tamper with QR codes to send victims to malicious sites that steal login and financial information ^{22Cybercriminals Tampering with QR Codes to Steal Victim Funds (PSA I-011822-PSA, 18 January 2022) · FBI Internet Crime Complaint Center (IC3) ↗}. The Bureau has also warned about a scam in which criminals mail unsolicited packages containing a QR code to trick recipients ^{23Unsolicited Packages Containing QR Codes Used to Initiate Fraud Schemes (PSA, 31 July 2025) · U.S. Federal Bureau of Investigation (FBI) ↗}.

Defensive habits matter. The NCSC recommends using the QR scanner built into your phone rather than a scanner app downloaded from an app store ^{17QR Codes - what's the real risk? · UK National Cyber Security Centre (NCSC) ↗}. After scanning a QR code, check the URL to confirm it is the intended site and looks authentic, since malicious domains often imitate real addresses with typos ^{22Cybercriminals Tampering with QR Codes to Steal Victim Funds (PSA I-011822-PSA, 18 January 2022) · FBI Internet Crime Complaint Center (IC3) ↗}. The FBI advises taking precautions before scanning any QR code that arrives through unsolicited messages or packages ^{23Unsolicited Packages Containing QR Codes Used to Initiate Fraud Schemes (PSA, 31 July 2025) · U.S. Federal Bureau of Investigation (FBI) ↗}.

The QR code is a two-dimensional matrix barcode developed in 1994 at Denso Wave, then a division of Denso Corporation, in Japan. The letters QR stand for “quick response”, a name reflecting the design focus on high-speed reading. It was created to ease barcode reading for Denso's manufacturing staff, built to carry large amounts of information efficiently and to be used freely by people everywhere. Masahiro Hara led the small team behind it, a two-person effort.

The symbology is defined by the international standard ISO/IEC 18004, first published in 2000 and now in its fourth edition, issued in 2024. That standard sets out the code's characteristics, encoding methods, symbol formats, error-correction rules and reference decoding algorithm. Its current edition carries the formal title “QR code bar code symbology specification”.

QR codes come in 40 symbol versions, each with a different number of modules. Version 1, the smallest, is a 21×21 grid, while Version 40, the largest, is 177×177; every version up adds four modules per side. At its maximum, Version 40 holds 7,089 numeric, 4,296 alphanumeric, 2,953 binary or 1,817 kanji characters.

Error correction allows the symbol to be restored if it becomes dirty or damaged, and four selectable levels are available. These are L at roughly 7%, M at roughly 15%, Q at roughly 25% and H at roughly 30%. Factories where codes get dirty often use the higher Q or H levels, clean environments with large amounts of data can use L, and Level M is the most commonly chosen. The Reed–Solomon code behind this capability was originally developed against noise in satellite and space-probe communications, and it corrects errors at the byte level.

Smaller variants followed the original code: the Micro QR Code, made a Japanese (JIS) standard in 2004, and the iQR Code with rectangular modules in 2008. The Micro QR Code spans 11×11 to 17×17 modules and holds up to 35 numerals. The rectangular rMQR Code, specified in ISO/IEC 23941:2022, holds up to 361 numerals in as little as 7×43 modules. It was designed for narrow spaces where the conventional QR code cannot be printed, and it holds more data than the Micro QR Code. The rMQR Code received ISO certification, so it can be used freely around the world, like the original QR code.

Denso Wave published the QR Code specifications so anyone could use them freely, and though it retained the patent rights it declared it would not exercise them — a decision that helped the code spread worldwide. The company holds several QR code patents but exercises them only in a limited way, waiving its rights to a key patent for standardized codes to encourage widespread use.