How Does a QR Code Encode Data?

Have you ever wondered what’s behind the complicated pixel-like square images known as QR Codes? How can QR Codes encode such versatile yet specific information? Due to their innovative design, QR Codes can be used for just about anything.

QR Code structure

A QR Code is most often in the shape of a square, as that is what QR Code scanners can recognize, as well as it maximizes their efficiency for holding and sending information. Their puzzle-like appearance contains seven crucial elements:

Positioning markings: these direct which way a Code is printed.

QR Code positioning markings

Alignment markings: for larger QR Codes, this element aids with orientation.

QR Code alignment markings

Timing pattern: these lines tell a scanner the size of the data matrix.

QR Code timing pattern

Version information: these sections specify which version of the QR Code is used. Out of a total of 40 different QR Code versions, versions 1-7 are used most often.

QR Code version information

Format information: format patterns include information regarding error tolerance and data mask pattern, making it simpler to scan the Code.

QR Code formation information

Data and error correction keys: this is where the actual data is shown.

QR Code data and error correction keys

Quiet zone: a space that helps to scan programs to differentiate between the QR Code itself and the surrounding materials.

QR Code quiet zone

QR Codes vs Barcodes

QR Codes can be confused with Barcodes, but there is an important difference. Whereas Barcodes can only be read horizontally, they are considered one dimensional. QR Codes can be read both horizontally and vertically, meaning they are two dimensional. A big reason why QR Codes were developed was due to the challenges that Barcodes face due to their limited ability to hold larger information sets.

Left: a QR Code, right: a Barcode

Why Barcodes were developed

The need for Barcodes arose out of Japan in the 1960s due to the increase in demand for retailers and supermarkets to hold a wider variety of items. Before this technology existed, cashiers had to document all purchases by hand, a nightmare for anyone working in this job full time. When it goes to the point where employees began to have resulting health issues, managers set out to find a solution. Hence, Barcodes were developed so that product purchases could be processed via scanning, which saved on time and costs.

QR Codes improved on Barcodes

Despite these advancements, this still wasn’t enough. Barcodes alone simply couldn’t hold the information that stores needed to manage product inventory. Eventually, store managers contacted a company called DENSO WAVE to develop a solution. Even with the large demand, the project was given to only two members, of which the leader was called Masahiro Hara. It was his ingenious design of using a square code that resulted in the QR Codes, largely because of their ability to hold more information and have faster scan times.

QR Code symbols

Quite technical in their concept, the square QR Code design has a high amount of flexibility for data input. The symbols function solely based upon machine reading (it’s not recommended to try to decipher it with the naked eye!). However, it is possible to see if a QR Code contains more or less information on how “busy” the QR Code looks.

Comparison of data amounts in QR Codes

QR Code symbols are broken into sections called modules. Each module has a certain size and can be indexed by the version number which ranges from 1-40. Specific symbols are split into bits stored within the modules and are grouped as 8 bits each. The reasoning for grouping bits together is that the Code has room for error or damage, meaning it can still be read. After this, a mask is placed over the symbols so a device can distinguish the pattern which makes up the QR Code. 

Why is a QR Code square?

The most clever point of a QR Code involves its square design. While Barcodes are still useful for some simple uses, the benefits of QR Codes extend far beyond Barcodes, which is why they are still popular today.

Higher data capacity

The biggest advantage of a QR Code over a Barcode is that it can hold literally hundreds of times the information that a Barcode can – and that in a smaller space as well. The key is the square structure that allows for a two-dimensional reading, i.e. both horizontal and vertical information.

Due to the fact that they hold so much information, QR Codes have many versatile ways they can be used. QR Code Generator includes free software that makes it simple to make custom QR Codes that can connect to a wide variety of consumer or personal information.

Improved error correction

On top of this, QR Codes can withstand much more damage than Barcodes. Most QR Codes have an error margin of 7-30%, which is of extreme importance when it comes to inventory management. QR Codes can be placed on product packaging that goes through thousands of miles of manufacturing, assembly, and distribution and is still readable.

Now that many industries have also recognized this total value for the use of QR Codes on any print material, the possibilities for their use are basically endless.

Easy to read

QR Codes also require less technical equipment to read. While Barcodes require special scanners, QR Codes can be read with any QR Code scanning app on cell phones, as well as software programs for desktops. In combination with the popularity of cell phones, this is the element of QR Codes that has brought their use into people’s daily lives across the globe. Some Apple cell phones now even include QR Code scanners directly through the camera. Samsung also offers the same capability on some cell phone models as well.

Customization features

To describe yet another benefit to QR Codes, they can also be customized and edited after completion (provided you have chosen a Dynamic QR Code). With QR Code Generator’s software, you can create a custom QR Code in just 30 seconds that includes individual colors, a logo, and a frame. There is also a wide variety of information that can be connected to the QR Code itself, making QR Codes a flexible way to enhance marketing campaigns.

What types of data can a QR Code encode?

To give an overview of just how many ways QR Codes can be used, here are the types of information that QR Code Generator enables you to connect QR Codes to:

QR Code TypePurpose
vCard Plus CodeConnect a user to a digital business card.
Facebook CodeLink to Facebook to gain more followers.
App CodeInstall an app from multiple app stores via one QR Code.
PDF CodeAdd downloadable PDF to any print material.
Social Media CodeDirect users to multiple social media accounts at once.
Coupon CodeDisplay a discount coupon for a product or service.
Business CodeAdvertise your business on an easily readable page.
Video CodeShare one or multiple videos.
Rating CodeCollect ratings easily.
Feedback CodeShare feedback surveys.
Event CodePlan and increase attendance for an event.
Dynamic URL CodeLink to any website which is changeable at any time.
Image Gallery CodeView multiple images in one place.
MP3 CodeShare an audio file in MP3 format.
Email CodeCollect and share email addresses instantly.
vCard CodeShare contact details to be added in seconds.
SMS CodeSend automated messages directly.
Text CodeSend text in any language and share it.
Static URL Code The standard way to connect a QR Code to any web page.

Pro tip: Use a Dynamic QR Code for marketing campaigns so that scan information can be tracked and edited at all times. Metrics like location, operating system, total scans, and timed scans are essential to monitoring any marketing campaign that uses QR Codes.

Do damaged QR Codes still work?

On average, QR Codes can resist damage of up to 30% of the total structure with no effect on the readability of the Code itself. This is possible due to duplications in the data, meaning redundant information is deposited into the Code to maximize its readability.

How to interpret a QR Code without a mobile phone?

If you don’t have a cell phone handy, it’s also possible to use desktop software to read a QR Code, though the process takes a bit longer. Using software like Barcode Reader, you can either enter a URL directly or if you only have the image of the QR Code, it can be uploaded and read. QR Codes, in general, are machine-readable only so it’s best to find a cell phone and use a scanning app, which can be done with just a quick tap of a button.

Adriana Stein

Adriana Stein is a Freelance Content Writer for Egoditor GmbH and is originally from Oregon, USA. She is now based in Hamburg, Germany, and specializes in creating and managing SEO and content marketing strategies for businesses across a variety of industries. Feel free to connect with her on LinkedIn!

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