id: 38
title: What is a QR Code?
date: 2011-09-17T15:37:15+00:00

permalink: /what-is-a-qr-code/

This is a post that I’ve constructed using a number of sources (linked at the bottom of this post) and from my own use of QR codes.


A QR code (abbreviated from Quick Response code) is a type of matrix barcode (or two-dimensional code) first designed for the automotive industry. More recently, the system has become popular outside of industry due to its fast readability and comparatively large storage capacity. The code consists of black modules arranged in a square pattern on a white background. The information encoded can be made up of any kind of data (e.g. binary, alphanumeric, or Kanji symbols).

QR codes storing addresses and Uniform Resource Locators (URLs) may appear in magazines, on signs, on buses, on business cards, or on almost any object about which users might need information. Users with a camera phone equipped with the correct reader application can scan the image of the QR code to display text, contact information, connect to a wireless network, or open a web page in the telephone’s browser. This act of linking from physical world objects is termed hard-linking or object hyperlinking.

QR codes can be used in Google’s mobile Android operating system via both their own Google Goggles application or 3rd party barcode scanners like ZXing or Kaywa. The browser supports URI redirection, which allows QR codes to send metadata to existing applications on the device. Nokia’s Symbian operating system features a barcode scanner which can read QR codes, while mbarcode is a QR code reader for the Maemo operating system. In the Apple iOS, a QR code reader is not natively included, but more than fifty paid and free apps are available with both scanning capabilities and hard-linking to URI available. With BlackBerry devices, the App World application can natively scan QR codes and load any recognised Web URLs on the device’s Web browser. Following an upcoming update, Windows Phone 7 will be able to scan QR codes through the Bing search app.


Created by Toyota subsidiary Denso Wave in 1994, the QR code is one of the most popular types of two-dimensional barcodes. The QR code was designed to allow its contents to be decoded at high speed.

Although initially used for tracking parts in vehicle manufacturing, QR codes as of 2011 are used in a much broader context. Uses extend from commercial tracking to entertainment and from product marketing to in-store product labelling. Many of these applications target toward mobile-phone users (via mobile tagging). Users may receive text, add a vCard contact to their device, open a Uniform Resource Identifier (URI), or compose an e-mail or text message after scanning QR codes. They can generate and print their own QR codes for others to scan and use by visiting one of several paid and free QR code generating sites or apps. Google has a popular API to generate QR codes, and Apps for scanning QR codes can be found on nearly all smartphone devices.

There are several standards in documents covering the physical encoding of QR codes:

  • October 1997
    AIM (Association for Automatic Identification and Mobility) International


  • January 1999
    JIS X 0510


  • June 2000
    ISO/IEC 18004:2000 Information technology
    Automatic identification and data capture techniques
    Bar code symbology
    QR code (now withdrawn)
    Defines QR code models 1 and 2 symbols.


  • September 1, 2006
    ISO/IEC 18004:2006 Information technology
    Automatic identification and data capture techniques
    QR code 2005 bar code symbology specification
    Defines QR code 2005 symbols, an extension of QR code model 2. Does not specify how to read QR code model 1 symbols, or require this for compliance.

At the application layer, there is some variation between implementations. NTT DoCoMo has established de facto standards for the encoding of URLs, contact information, and several other data types. The open-source “ZXing” project maintains a list of QR code data types which are discussed in the ‘Embedded Media into QR Codes’ section of this post.


The technology has seen frequent use in Japan and South Korea; the United Kingdom is the seventh-largest national consumer of QR codes. In the US, QR Code usage is expanding. During the month of June 2011, according to one study, 14 million mobile users scanned a QR Code or a barcode. 58% of those users scanned a QR or bar code from their home, while 39% scanned from retail stores. 60% of the 14 million users were men between the age of 18-34.

While the adoption of QR codes in some markets has been slow to begin (particularly in markets such as the United States where competing standards such as Data Matrix exist), the technology is gaining some traction in the smartphone market. Many Android, Nokia, Blackberry handsets, and the Nintendo 3DS, come with QR code readers installed. QR reader software is available for most mobile platforms. Moreover there are number of online QR code generators where users can create QR codes for their own needs.

Embedded Media into QR Codes

The actual idea of embedded media into a QR is a bit of a myth. QR codes can only store alphanumeric characters and a selection of symbols. You can invoke different types of actions by using URL/protocol schemes which are defined by each QR reader. The following list details the types of URL schemes that you can use.

  1. Contact Information
QR codes can contain contact information so someone can easily scan a QR code, view your contact details, and add you on their phone. You can input your name, phone number, e-mail, address, website, memo, and more. I've commonly seen these used on business cards, for instance. You give someone a business card, they see a QR code on the back, scan it with their phone, and easily add your contact info to their phone.
  1. Calendar Event:
If you have an event you want to promote, you can create a QR code containing info for that event. QR codes containing event info can contain event title, start and end date/time, time zone, location, and description. This could work well on an event flyer or possibly even on a website promoting.
  1. E-mail Address:
Nice and simply, eh? A QR code can contain your e-mail address so someone can scan the code, see your e-mail, and then open an e-mail on their phones. If your call to action is mostly to have someone e-mail you, this would be great.
  1. Phone Number:
Maybe e-mail isn't immediate enough and you want someone to call. Link them up to a phone number.
  1. Geolocation:
If you have an event you want to promote, you might want to stick a QR code linking someone to a Google Maps location. This will allow someone to scan your QR code and get directions so they don't have to manually type in an address. Although some may prefer to type it in, it doesn't hurt to give them another option.
  1. SMS:
QR codes can populate a text message with a number and message. You can have your QR code send you a text saying, &#8220;Tell me more about XYZ&#8221; for instance. This is great when paired with text message marketing.
  1. Text:
You can also just have a sentence or a paragraph of text. This could be fun for having some type of QR code based game where you can leave hints in QR codes.
  1. Wifi Network:
Do you hate telling someone a long WEP wireless key that's a pain to type out on a mobile phone? Set it up so someone can scan a QR code and automatically configure wifi on their phones.
  1. URL:
Don't think little of this 3-letter data type. This is where the possibilities become endless. You can use a link that takes someone to your Facebook fan page or Twitter profile. You can also link someone to a YouTube video. Or maybe you want someone to pay for something via PayPal.

Did I mention all of these services have mobile-friendly versions of their website? That is, if you link someone to your Twitter page they'll be redirected to a version that's built specifically for their smartphone? Don't forget to make sure the link goes to a website that's optimised for mobile devices.


The use of QR codes is free of any license. The QR code is clearly defined and published as an ISO standard. Denso Wave owns the patent rights on QR codes, but has chosen not to exercise them. In the US, the granted QR code patent is US5726435. In Japan it is JP2938338. In Germany it is DE69518098. (The European Patent Office granted patent EP0672994 to Denso Wave, but Denso only “nationalised” the patent grant in Germany.) The term QR code itself is a registered trademark of Denso Wave Incorporated.

Risks of using QR Codes

Malicious QR Codes combined with a permissive Reader can put a computer’s contents and user’s privacy at risk. QR Codes intentionally obscure and compress their contents and intent to humans. QR codes are easily created and may be affixed over legitimate QR Codes. On a smartphone, the Reader’s many permissions may allow use of the camera, full internet access, read/write contact data, GPS, read browser history, read/write local storage, and global system changes.

Risks include linking to dangerous websites with browser exploits, enabling the microphone/camera/GPS and then streaming those feeds to a remote server, exfiltrating sensitive data (passwords, files, contacts, transactions), sending email/SMS/IM messages or DDOS packets as part of a botnet, corrupting your privacy settings, stealing your identity, and even containing malicious logic themselves such as JavaScript or a virus. These actions may occur in the background whereas the user only sees the Reader open a harmless webpage.

Commercial Uses

The use of commercial QR codes is increasingly greatly. The recent Red Hot Chilli Peppers album adverts for the album “I’m With You” had a creative QR code within the posters as Catalina Cadena notes in her blog post.

Data capacity

The amount of data that can be stored in the QR code depends on the character set, version and error correction level.

Error Correction

Codewords are 8 bits long and use the Reed–Solomon error correction algorithm with four error correction levels. The higher the error correction level, the less storage capacity. At the highest error correction level it is possible to create artistic QR codes that still scan correctly, but contain intentional errors to make them more readable or attractive to the human eye, as well as to incorporate colours, logos and other features into the QR code block. While the exact number of errors that can be corrected depends on the size of the symbol and the location of the errors, the following table lists the approximate error correction capability at each of the four levels:

  • Level L — 7% of codewords can be restored
  • Level M — 15% of codewords can be restored
  • Level Q — 25% of codewords can be restored
  • Level H — 30% of codewords can be restored

Uses of QR

  1. Business Cards.
    Stick a QR code on the back of your business card and have it link to your phone number, send a text message, link to your website, or even take someone to a Youtube video.

  2. Flyers.
    Handing out flyers door-to-door? Or maybe you want to spread the news about an event in a new and innovative way? Slap a QR code on it and link to an event page or a video describing more about the event. Check out how one clothing retailer is doing this. You can also add social media icons so people can share.

  3. Billboards.
    This one way communication channel just became interactive. Calvin Klein used QR codes on billboards in New York and Los Angeles with their Uncensored campaign. It linked to a page with a mobile video and Twitter/Facebook share icons. Simple? You bet. Learn more about it.

  4. Comics.
    That’s right, QR codes have been used in comics. It was done with Donald Duck for kids!

  5. Education.
    Use QR codes next to math problems in math books that pull up a video that teaches students how to complete certain problems. Let’s just hope they scan the QR code after they answered it! I picked up this idea on Youtube.

  6. Articles in Magazines/Newspaper.
    Magazine publishers can use QR codes in articles that link to more info on the article, a video, or even a discussion board. Wait. Stop. Think about that. Another one-way communication channel that is now engaging. Imagine someone reading an article, wanting to voice their opinion and leave a comment like they would on a website blog, scanning a QR code, and then leaving comments on an article they found in the paper medium. Talk about in-the-moment engagement. Simply fascinating.

  7. For Sale Signs on Homes.
    Real Estate, anyone? Print a QR code on a for sale sign on a home that connects the mobile user to a mobile website that shows them more info on the home and includes a video with a walk-through of the home (which they wouldn’t otherwise be able to see). Or just link to a Youtube video. Talk about point-of-experience!

  8. Comment Cards.
    Tired of paper comment cards? Want to reduce error and capture feedback at the point-of-experience? Or maybe there is a trust issue with the manager and you think he’s trashing some bad comment cards? Either way, mobile web-based comment cards allow for convenience and meet the consumer where there are. Comments can be e-mailed to someone and added to an excel file if need be. Theoretically, someone can file a complaint and a manager (as well as corporate, if needed) can receive the complaint via e-mail and respond to it before the customer has even left the building. Talk about real-time.

  9. Presentations.
    More and more I’ve seen less of the traditional speaker presentations. Audiences want to engage during presentations and throw in their two cents, just like they do on Twitter. The unGEEKED e’lite conference is built on this idea. One way to engage the audience is to stick a QR code in a presentation. Maybe the audience can scan it and be put on a mailing list, ask a question, or give their input on the presentation at the end, all via the mobile web. This would work best at conferences where early adopters are present.

  10. Clothing.
    Want to be different? How about you stick a QR code on a shirt. How’s that for standing out against the crowd? Or clothing companies can use QR codes on tags to display colour, style, size, and more about that item.

  11. Television.
    This is extremely fascinating. Again, a one way communication channel… is now interactive. QR codes on TV allows for viewers to answer quizzes, sign up for a mailing list, find a Facebook fan page, and more. Although executed poorly, FOX tried this.

  12. Books.
    How about a QR code at the end of each chapter, which links to a discussion board where readers can share comments on a chapter. Amazing. Or maybe you want to describe a concept with digital media. Video, anyone? Or maybe the author wants to link you to a page with errata.

  13. Outdoor Games.
    Ever participate in a scavenger hunt? With QR codes, you can leave digital tips for people. How about a video hint or video riddle?

  14. Direct Mail.
    QR codes on direct mail allows for people to scan and learn more about a product or service.

  15. Instruction Manual.
    With some products, a paper manual isn’t enough. People need a video to help visualise how things go together. Or maybe you just want to give that personal feeling and talk about why it’s awesome.

  16. Interactive Menus.
    In restaurants, consumers can scan QR codes in the menu and watch a video on how that dish was prepared, see the ingredients, learn more about the executive chef with an interview, or even the staff. Stop. Think about that personal connection for a minute. Think about the story that someone can go tell their friends. They came to order food, but their experience was heightened because they were also able to walk away with a recipe for their favorite dish (or something more). That is remarkable, as Seth Godin says. Again, the possibilities are endless. What’s important is the creative process and brainstorming.

  17. Cereal Box.
    Cereal boxes already have games on them, but how about games on a smartphone? Or maybe you want to have a “story of the day” or talk about what the brand is doing. This is a completely new way to engage with consumers.

  18. Products.
    QR codes can be used on products to connect real life to the digital world. Maybe you want to build awareness for a Facebook fan page or a Twitter account.

  19. Facebook Like.
    A service called Likify allows someone to do exactly that: like your Facebook fan page. Learn more about them.

  20. Call/E-mail Us.
    Simple enough? Have a QR code that brings up your phone number so someone can easily scan and call you or send you an e-mail.

  21. Coupons.
    Use a QR code to link to a special coupon that is shareable via social media. It can be tracked and turned off at any time. Goodbye paper coupons! (Did I mention this is environmentally friendly, too?)

  22. Name Tags.
    Although the idea of someone coming up and scanning your name tag at a conference sounds kind of funny, it can definitely help differentiate you and be a great conversation starter. There is a standard for storing contact info on QR codes. Use quiQR to create your virtual contact card today so someone can easily add you as a contact on their phone.

  23. Website Contact Us.
    If you already cater to your mobile audience, you can use QR codes on your contact us page. Maybe you want to link them to your mobile resource and remind them to bookmark it so they can use it on the go. Or maybe you want to make it so they can easily scan a QR code and call you.

  24. Conferences.
    Conferences can use QR codes for speaker feedback or conference feedback and evaluation. Attendees can share their thoughts via their mobile phone, and not a paper card with hard-to-read handwriting.

  25. Event Tickets.
    On a printed ticket, QR codes can be used to link to a video introduction to the event, or maybe link to a free MP3 download for a band. This is also good for tracking tickets, which Eventbrite does.

  26. Window Displays.
    Use QR codes on windows displays to give those window shoppers one more thing to look at (and talk about!). It can link to a video with someone talking about the product (very personal), or maybe you want to highlight certain features about the product.

  27. Classified Ads.
    Selling a car? Hiring someone? Link to a personal video on Youtube which has you expanding on the opportunity or telling people why it’s a good one.

Variants of QR Codes

Micro QR code is a smaller version of the QR code standard for applications with less ability to handle large scans. There are different forms of Micro QR codes as well. The highest of these can hold 35 numeric characters. Standard QR code is the QR code standard for applications that possess the ability to handle large scans. A standard QR code can contain up to 7089 characters, though not all QR readers can accept that much data.

Although encrypted QR codes are not very common, there are a few implementations. An Android app, for example, manages encryption and decryption of QR codes using a secure AES 128 algorithm. A special form of secure quick response codes utilising public key encryption are SKS codes which have identical appearance to normal QR codes. SKS codes were designed for one-time-use and are created by encrypting a precursor hardware security token such as the CID written in the ROM of a microSD card, applying a time stamp and displaying the code on for example the high resolution screen of a mobile handset. SKS codes are closely analogous to One-time pad which are highly secure and can therefore be used for applications demanding high security such as mobile financial transactions. SKS codes in fact combine the CID and GMT with other proprietary data related to the transaction, an assembly of datum which never occurs again and which is discarded after being decrypted and processed on the transaction server. SKS codes were first developed in 2010 by Japanese company Yodo KK and are patent pending.