# Quick Response (QR) Code: What They Are, How They Work, and Types

![Quick Response Code (QR): A type of barcode that stores information and can be read by a digital device.](https://www.investopedia.com/thmb/R6B06tnmWvivfdiLoVtmrSnFZHY=/1500x0/filters:no_upscale():max_bytes(150000):strip_icc()/quick-response-qr-code.aspp-Final-4b2216e6f1e24990a31030c33b2490b7.png)

*QR code usage became widespread in the hospitality sectors as a result of the pandemic. — Investopedia / Theresa Chiechi*

> **Definition**
>
> A quick response (QR) code is a kind of matrix barcode that utilizes black squares on a white background to encode information, which can be read by imaging devices.

## What Is a Quick Response (QR) Code?

A quick response (QR) code is a type of barcode that can be scanned by a digital device and that stores information as a series of pixels in a square-shaped grid. QR codes bridge the physical and digital worlds, as people can scan menus and posters for information with their cellphones.

However, QR codes are used to do more than tell you what appetizers are on special at your local restaurant. Inventory managers hope they gain wider use to track product information in the [supply chain](https://www.investopedia.com/terms/s/supplychain.asp), not just in marketing and advertising campaigns. QR codes are considered an advance over the older, unidimensional barcodes and were approved as an international standard in 2000 by the [International Organization for Standardization (ISO)](https://www.investopedia.com/terms/i/international-organization-for-standardization-iso.asp).

### Key Takeaways

*   Quick response (QR) codes are square-shaped matrices of dark or light pixels that encode and quickly retrieve data using computer devices.
*   An enhancement on traditional barcodes, QR codes can store vastly more information and are used in various applications, from supply chain management to [cryptocurrency](https://www.investopedia.com/best-crypto-exchanges-5071855) wallet addresses.
*   There are also several versions and variations of QR codes that are customized for different purposes or can store greater amounts of data.

## How QR Codes Work

QR codes were developed in the 1990s 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](https://www.investopedia.com/terms/b/barcode.asp), which require a beam of light to bounce off the parallel lines, mobile phones can digitally scan QR codes.

QR codes typically consist of black squares arranged in a grid (matrix) on a white background and are read by specialized software that can extract data from the patterns in the matrix. These codes can contain more information than traditional barcodes and primarily handle four modes of data: alphanumeric, numeric, binary, and Kanji.

Despite the greater capacity, QR codes haven't proven as popular with consumers as was expected. Rather than being created by consumers to share information, they're most commonly associated with [marketing](https://www.investopedia.com/terms/m/marketing.asp) campaigns.

QR codes have become more widespread in facilitating digital payments and [cryptocurrency](https://www.investopedia.com/terms/c/cryptocurrency.asp) 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 below encodes this webpage’s URL.

![QR code encoding this webpage’s URL](https://www.investopedia.com/thmb/tJq-mQKa7VHC4JG76FATefpzN1Y=/1148x0/filters:no_upscale():max_bytes(150000):strip_icc()/qr-code-bc94057f452f4806af70fd34540f72ad.png)

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

## QR Codes vs. Barcodes

Barcodes are commonly found on the back of product packages and convey data using a combination of various widths of parallel lines, which can be read by machines that have an optical scanner.

The barcode revolutionized the way companies managed [inventories](https://www.investopedia.com/terms/i/inventory.asp) and pricing, and it was first put to practical use in the 1960s by United States 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. The impact of this humble set of lines is hard to overstate: Without them, the never-ending cascade of products cramming every aisle of our stores would be much harder to inventory and ship.

Barcodes are typically used when a simple identification is needed. Supermarkets use them to track product prices and inventory. Libraries use barcodes for book identification and checkouts. Shipping companies utilize barcodes to track packages throughout the delivery process.

QR codes, meanwhile, are commonly used when a large amount of information needs to be shared. For instance, they're often found on event tickets to quickly provide details or on advertisements to link directly to a website. QR codes can also be used in restaurants, enabling customers to view digital menus by scanning the code.

> **Fast Fact**
>
> 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'd have to find a salesperson or request extra documentation.

Some envision even broader applications for QR codes in streamlining inventory and supply chains in the years ahead. Beyond encoding website URLs, QR codes can store expansive amounts of data, opening possibilities like integrating detailed product information into codes. In the future, scanning a code could show everything from a product’s manufacturing data to its transportation history to precise expiry dates.

A few companies are even experimenting with using QR codes to tie digital information to individual products rather than entire product lines. With this level of precision, scannable QR codes could provide consumers assurance about the origins, ingredients, or components of the item they're purchasing. Supply chain managers may also see efficiency improvements if items can be traced to specific factories, batches, and delivery dates.

As the possibilities expand, QR codes may radically change how data flows between physical products and digital systems, bridging digital life and the real world.  

### QR Codes vs. Barcodes

QR Codes

*   Used for sharing extensive information  
    
*   Commonly found on event tickets and ads
    
*   Enable digital menu viewing in restaurants
    
*   Gaining wider use to track inventory in real time
    

Barcodes

*   Used for simple identification  
    
*   Track prices and inventory in stores
    
*   Aid in checkout and package tracking
    

## Types of QR Codes

Many QR code types may be used for different items. Here are a few:

*   **Micro QR code**: A smaller version of a traditional QR code for when space is limited. Micro QR codes can vary in size, but the smallest is 11 × 11 modules, encoding up to 21 alphanumeric characters.
*   **Model 1 QR codes**: Model 1 is the prototype of Model 2 and Micro QR. One to 14 versions are registered to the Automatic Identification Manufacturers International (AIMI) standard. It can encode up to 1,167 numerals.
*   **Model 2 QR codes**: Model 2 has an alignment pattern for better position adjustment and contains greater data density than Model 1. Versions one to 40 are registered to the AIMI standard, with version 40 capable of storing up to 7,089 numerals.
*   **iQR codes**: These can be created in squares or rectangles where space or shape is an issue. It can be made in 61 formats.
*   **SQRC**: This features a restricted reading function to contain private information.
*   **Frame QR**: This has a customizable frame that can contain larger data in formats like graphics, illustrations, or photos.

## QR Codes During COVID-19

The pandemic dramatically increased the use of QR codes, with a reported 25 times surge for restaurants and seven times surge for hotels as societies shifted toward touchless interactions.

Businesses in the hospitality sectors, such as restaurants and bars, utilized QR codes for safe communication (like digital menus, among many other use cases) and transactions.

While paper menus have largely returned, the use of QR codes continued post-pandemic. COVID-19 demonstrated the adaptability and versatility of QR codes, suggesting their potential for use in various industries.

## Explain Like I'm 5

A QR code is essentially an advanced type of barcode that's able to contain a substantial amount of data. Information is typically encoded as a series of tiny black squares arranged across a white background. Imaging devices, such as a smartphone's digital camera, can download or already have software capable of translating a QR code's pattern into readable data.

Once a code's been successfully scanned, the stored data will prompt a specific action from the device, which varies based on the type of information. For example, if a QR code contains a website's URL, then your device may present you with a link that'll take you to that webpage. Meanwhile, if the encoded data is a contact card, it'll likely give you the option of saving the contact information.

Because of how QR codes are structured, devices can rapidly read them from nearly any angle. And since information doesn't have to be coded in a specific direction, QR codes have extra space for additional data. This is also why barcodes aren't able to hold as much information, as it can only be coded in one direction (i.e., across).

## Are QR Codes Only Black and White?

No, QR codes aren't just black and white. They can be customized with different colors and designs.

## What’s the Largest QR Code Ever Made?

The largest QR code was made on crop land in Indiana in 2022. U.S. brewery D.G. Yuengling & Son Inc. and Chalfant Family Farms made the code on a 1,721,344-square-foot area (about a quarter-mile long by a quarter-mile wide).

## Do QR Codes Expire?

No, QR codes generally don't expire. Once created, they can be used indefinitely unless the linked information is changed or removed.

## Are QR Codes Secure?

While QR codes cannot carry viruses, they can link to malicious websites. Users should only scan QR codes from a trusted source.

## The Bottom Line

QR codes are intuitive to use with modern smartphones. Their advantages include increased customer engagement, more accessible access to information, and digital utility in areas like digital signage. However, potential cons include security concerns, as they can link to malicious websites and a gateway to a person’s private information.

Their use, already expansive in Asia, grew considerably in Europe and the U.S. during the pandemic and has remained widely used. Supply chain and efficiency managers see far broader applications for QR codes to track products in real time.

> **Article Sources**
>
> 1.  QR Code.com. “[QR Code Standardization](https://www.qrcode.com/en/about/standards.html).”
>     
> 2.  Denso Wave. “[QR Code Development Team Becomes First Japanese Winner of European Inventor Award](https://www.denso-wave.com/en/adcd/info/detail__251.html).”
>     
> 3.  Electronic Imaging Materials. “[Barcode History—How Early Barcodes Changed Our Lives](https://barcode-labels.com/early-barcodes-brief-history-how-barcodes-changed-our-lives/).”
>     
> 4.  QR Code.com. “[Micro QR Code](https://www.qrcode.com/en/codes/microqr.html).”
>     
> 5.  QR Code.com. “[QR Code Model 1 Model 2](https://www.qrcode.com/en/codes/model12.html).”
>     
> 6.  QR Code.com. “[iQR Code](https://www.qrcode.com/en/codes/iqr.html).”
>     
> 7.  QR Code.com. “[Types of QR Code](https://www.qrcode.com/en/codes/).”
>     
> 8.  dentsu X. “[The Rise of QR Codes During COVID-19](https://www.dxglobal.com/insights/the-rise-of-qr-codes-during-covid-19/).”
>     
> 9.  QR Code.com. "[History of QR Code](https://www.qrcode.com/en/history/).
>     
> 10.  MyQRCode. “[What Are the Biggest QR Codes Ever Made?](https://myqrcode.com/blog/what-are-the-biggest-qr-codes-ever-made)”