QR Code Reader: How Does It Work?

Ilaha Mammadova

Nov 28, 2023

5 min read

QR Code Reader

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A QR code reader is software or an application that decodes QR codes using a device equipped with scanning capabilities. A QR code reader works by scanning a QR code to decode information within it using a phone, tablet, or any device equipped with QR code scanning capabilities. There are 4 benefits of a QR code reader, including rapidly retrieving information, compatible integration with various devices, seamlessly integrating with apps and services, and offline work. 

There are 4 risks of QR code readers, including access to information on devices, exposure to risky information, creation of fake versions, and challenges with reading certain QR codes. There are 7 components of a QR code, including finder patterns, alignment patterns, timing patterns, format information, version information, data and error correction area, and quiet zone.

QR codes store various characters, including numeric, alphanumeric, kanji, kana, hiragana, and byte characters. A standard QR code accommodates up to 7,089 numeric characters. One significant distinction between QR codes and traditional barcodes is that QR codes hold much more information without requiring specialized scanning equipment. Smartphones, laptops, desktops, and tablets serve as QR code readers. 

The beauty of a QR code reader lies in its accessibility. Scanning QR codes with smartphones is convenient for users. There is no need for any other app with all the scanning capabilities of IOS, ANDROID, and computer cameras. However, it is essential to exercise caution when scanning QR codes, as malicious individuals exploit them for nefarious purposes.

What is a QR code reader?

A QR code reader is software or an application that decodes QR codes using a device equipped with scanning capabilities. A QR code reader simply employs the phone's camera to scan QR codes, eliminating the need for additional tools with most smartphones. The functionality of the QR code reader is facilitated through software embedded within the phone's operating system. QR code reader applications are necessary to download in cases where a phone lacks built-in scanning capability.

Four types of QR code readers are available, including mobile apps, camera apps, web-based readers, and integrated reading applications. The mobile app is employed to scan code with phones that do not possess built-in scanning capability. The applications are downloaded and used. Camera apps on devices with QR code reading abilities scan QR codes without needing external tools. 

Web-based QR code readers operate directly within a web browser to scan QR codes on a computer. Integrated reading applications are integrated into other messaging, payment, or social media apps to decode QR codes for different purposes. Therefore, it is necessary to remember 4 types of QR code scanners if the question "What is a QR code reader or scanner?" is asked.

How does the QR code reader work?

A QR code reader works by scanning a QR code (Quick Response Code) to decode information within it using a phone, tablet, or any device equipped with QR code scanning capabilities. QR code reader software embedded in the device's camera, whether a phone, tablet or dedicated QR code scanner, facilitates the process. A QR code reader application is installed, allowing it to scan codes with a phone and decode the information if devices lack built-in QR code scanning capabilities. The QR code reader decodes the information within the QR code (Quick Response Code), which appears on the device screen once the code is scanned.

QR codes consist of black modules that house the data within them. The black modules create various patterns, each serving a specific purpose. The QR code reader identifies QRs more swiftly than reading an alphabet of words due to the error correction level and patterns of QR codes. The patterns determine the QR codes' orientation, size, and position, facilitating faster scanning by the QR code reader. The error correction level ensures that the QR code is still read by the QR code reader, even with damage or distortion. A higher error correction level makes it easier for the QR code reader to interpret the information accurately. Therefore, explaining the simple scanning process with any device is enough if someone asks, "How do QR codes work.”

How do the black lines represent different characters for QR code readers?

The black lines or squares in a QR code do not directly represent different characters for the QR code reader. They form a binary representation. The QR code data is converted into a sequence of bits through the encoding scheme of QR codes. The grid composed of white and black modules serves as the foundation. Each module represents a single binary bit. Binary data is represented by combining these black and white modules in a grid pattern. The QR code reader decodes the binary data and extracts the embedded information during scanning.

The data contained within the QR code consists of various types, such as numeric and alphanumeric characters, kanji, kana, hiragana, and byte characters. Numeric characters exclusively encode numbers, each represented by 4 bits of data. Alphanumeric characters encompass numbers, letters, and other characters, each represented by 6 bits of data. Byte characters enable the encoding of binary data, with each character represented by 8 bits of data. Kanji characters are represented by 13 bits of data, while Kana and Hiragana characters are represented by 8 bits specific to the Japanese writing system. Providing information about characters is ideal for a more detailed explanation when answering the question, "What is a QR code."

How does a QR code differ from a barcode?

QR codes differ from a barcode in several aspects, including the amount of information, type of information contained, scanning capabilities, visual appearance, and intended applications. QR code is two-dimensional, providing distinct advantages when looking at QR code vs. barcode. It is seen that QR codes allow information to be encoded vertically and horizontally when analyzing the difference between a QR code and a barcode. QR codes accommodate numeric and alphanumeric data, whereas barcodes only encode numerical information.

QR codes store more information due to their higher data capacity. QR codes are scanned from any orientation due to their two-dimensional nature. QR codes are scanned using a standard phone camera, while barcodes require a specialized scanner. QR codes house various types of information depending on the intended purpose. It includes social media account details, website links, and other relevant data.

Can I scan a QR code using a barcode reader?

No, you can not scan a QR code using a barcode reader. QR codes are two-dimensional codes that differ from barcodes, encompassing information vertically and horizontally. It is seen that the characteristic of a QR code enables it to be scanned from any orientation when comparing a QR code vs. a barcode. QR codes store various types of information due to their large capacity. QR codes accommodate a substantial amount of diverse information, typically numerical data arranged in parallel straight lines. Therefore, barcode readers do not scan QR codes.

What are the components of a QR code?

The 7 components of a QR code are listed below.

  • Finder patterns: The finder patterns are positioned at the top-right, top-left, and bottom-left corners of every QR code. The finder patterns determine the QR code's size, orientation, and shape, ensuring that QR code readers effortlessly scan them. The presence of finder patterns aids in determining the correct alignment and scanning technique for the QR code.
  • Alignment pattern: The alignment pattern is smaller than the finder pattern within the QR code and adjusts the position of the QR code based on the amount of information contained in the code. The purpose of finder patterns is to facilitate more precise QR code scanning by QR code readers.
  • Timing pattern: The timing pattern moves vertically and horizontally between finder patterns. The timing pattern plays a crucial role in determining the width of the data matrix.
  • Format information: The format information within a QR code includes details regarding the error tolerance level and the data mask pattern. The format information plays a vital role in the scanning QR codes process, ensuring efficient and quick scanning.
  • Version information: The version information of a QR code is responsible for indicating the specific version of the code. The version information is around the QR code's top-right and bottom-left finder patterns.
  • Data and error correction area: The data and error correction area encompasses the largest portion of the QR code. The error correction area includes the data area. An error correction area guarantees that the QR code reader interprets the code, even if it has been damaged to some extent.
  • Quiet zone: The quiet zone isolates the QR code from its surroundings on all sides of the QR code. The quiet zone facilitates easier readability for the QR code reader by clearly separating the code and its surrounding elements.


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What are the benefits of a QR code reader?

The 4 benefits of a QR code reader are listed below.

  • Rapidly retrieves information: The QR code reader swiftly captures information using the device's camera and promptly displays it on the screen within seconds.
  • Seamlessly works with various devices: The QR code reader is not limited to smartphones. QR scanners are compatible with tablets and computers, quickly retrieving information across multiple devices.
  • Seamlessly integrates with apps and services: The QR code reader seamlessly integrates with various applications, including payment systems, messaging platforms, and social media tools, expanding its functionality beyond standalone scanning.
  • Effectively works without the internet: The QR code reader offers offline services depending on the type of QR code. An internet connection is unnecessary for static QR code solutions during scanning.

What are the risks of a QR code reader?

The 4 risks of QR code readers are listed below.

  • Access to information: The QR code reader applications access information on phones. QR code reader applications connect to the phone's camera to access information, such as contacts.
  • Exposure to risky information: The QR code reader inadvertently redirects users to dangerous links and websites when a QR code is scanned.
  • Creation of fake versions: The QR code reader scammers create counterfeit versions, deceiving users into believing they are legitimate. Users’ personal or card information is compromised when unsuspecting users download fake versions onto their devices.
  • Challenges with reading certain QR codes: The QR code readers encounter difficulties reading QR codes with low error correction levels, physical damage, or varying lighting conditions in specific scenarios.

What devices can be used as QR code readers?

Smartphones, tablets, desktops, and laptops can be used as QR code readers. QR codes are scanned for iPhone and iPad devices running iOS 11 and above using the camera. QR codes are scanned with the device's camera starting from Android 9 and above in the case of Android devices. An additional application must scan codes with a smartphone if the device does not meet the iOS 11 or Android 9 requirements or has not been updated. A dedicated scanner application is not required. The device's camera is sufficient for updated devices. The link appears on the screen within seconds by simply holding the camera over the QR code. QR codes are scanned using computers, laptops, and desktops with webcams or front-facing cameras. A link is displayed on the screen and directs to the information by clicking when a computer QR code reader scans.

How is imaging able to read QR codes?

Imaging technology is able to read QR codes through an image sensor and analyze them using a programmed processor. Firstly, an app with scanning capabilities such as Google Lens, Google Photos, or QR code image reader is launched, and the desired QR code image is selected from the device's photo library. The image is captured, and the processing algorithm extracts its patterns. Secondly, the pattern analysis process commences, decoding the QR code data. Thirdly, the link or other relevant information is conveniently displayed on the screen for the user's access upon successful decoding. QR codes in the form of images are effortlessly scanned, and the contained information is promptly delivered to the user due to the image scanning and processing capabilities.

How many characters can a QR code store?

A standard QR code can accommodate 7,089 numeric characters, equivalent to 4,296 alphanumeric characters, due to uppercase and lowercase letters and numeric digits in the alphanumeric character set. The character of the QR code count reduces to 2,953 when binary data is encoded within the QR code. The count further decreases to 1,817 in the case of Kanji's and Kana's characters. However, it's important to note that the storage capacity varies across different QR code types, particularly with advancements and updates. Factors such as the error correction level, version, and stored content affect the QR code's capacity. For instance, a micro QR code is the smallest QR code and stores 35 numerical characters, while IQR codes accommodate up to 40,000 numerical characters.

How to scan QR codes on an iPhone

To scan QR codes on an iPhone, 4 steps are listed below.

  1. Launch the camera app. Open the camera application to capture pictures or record videos on the phone's screen.
  2. Scan the QR code. Make sure the camera's viewfinder covers the QR code completely.
  3. Click the screen banner. Tap on the banner that appears on the screen to proceed.
  4. Access information. Access the information on the page the link is referring to.

To add a QR code reader to the control center on an iPhone, 4 steps are listed below.

  1. Open the settings. Open the settings menu on the phone's screen.
  2. Navigate the control center. Navigate to the control center section once in the settings.
  3. Add a QR code scanner. Tap the "+" sign to add a QR code scanner.
  4. Scan QR codes from the control center. Scan codes with a smartphone in seconds, regardless of sufficient lighting, with the QR code scanner added to the control center.

How to scan QR codes on an Android Phone

To scan QR codes on an Android Phone, 4 steps are listed below.

  1. Open the camera app. Access the camera application from the menu on the phone's screen.
  2. Scan the QR code. Ensure that the QR code is fully captured within the camera's view. Tap on the Google Lens icon at the top of the screen and scan the code with a phone using Google Lens.
  3. Click on the banner. Click on the banner on the screen to reveal the information contained within the QR code.
  4. Access the information. Access the information stored within the QR code after tapping the banner.

How to scan a QR code on the computer

To scan a QR code on a computer, 6 steps are listed below.

  1. Open the camera app. Access the app by searching for "camera app" in the search section on a computer.
  2. Access settings. Navigate to the settings menu to activate the QR code scanner.
  3. Enable the QR code scanner. Locate the "related settings" option and proceed to the "try new experimental features" section within the settings.
  4. Activate the QR code scanner. Follow the instructions to activate the QR code scanner using the designated barcode scanner button.
  5. Scan the QR code. Position the camera towards the QR code on the computer screen. Scan the QR code on a computer within a few seconds. A link appears in a banner on the screen.
  6. Access the information. Click on the link in the banner to access the information associated with the QR code.

What are the two main types of QR codes?

The two main types of QR codes are listed below.

  • Static QR codes: Static QR codes are a type of QR code that remains unalterable once generated. Static QR codes are used indefinitely without any scan limits once created. However, modifications of static QR code information within them are not feasible. Solutions of static QR codes are scanned without an internet connection. Users simply use the phone's camera scan codes with a smartphone. It is directed to the linked information even without an internet connection. Static QR codes do not track scans and are not commonly used for retargeting. The URLs embedded within static QR codes tend to be longer, resulting in slightly longer scanning times.
  • Dynamic QR codes: Dynamic QR codes are one of the types of QR codes that are modified even after their creation. The flexibility in altering dynamic QR code data makes them highly useful for various purposes, including marketing initiatives. Scanning a Dynamic QR code necessitates an internet connection since it redirects to an online destination. One advantageous feature of Dynamic QR codes is their ability to track scans. Users gather insightful data such as the number of times the QR codes were scanned, the timing of the scans, the devices used for scanning, and the geographical locations from which they were scanned by accessing the dashboard. Employing an embedded short URL within Dynamic QR codes offers the benefits of a swifter scanning process.

What are the different applications of QR codes?

The 10 different applications of QR codes are listed below.

  • Marketing: QR codes are utilized in diverse marketing campaigns, encompassing both digital and traditional approaches, to provide information to customers swiftly. The codes are displayed on billboards, posters, or in-store displays, allowing customers to scan them or be entirely delivered online.
  • Payment: QR codes are convenient, offering a quick and seamless transaction process. The payment concludes when one party presents a QR code to the other, who then scans it to make a payment.
  • Coupons: QR codes play a significant role in creating various discount coupons. Companies enable personalized coupons for customers by conveying comprehensive information using QR codes.
  • Surveys: QR codes are conveniently employed in surveys to gather customer opinions about products or services, pose diverse questions, and facilitate improvements based on the responses received. Users access the survey form and fill in all the required information with just one scan.
  • Business cards: QR codes incorporated into business cards enable individuals and companies to reach a broader audience more swiftly. Users easily share it with others while having the option to print any desired information directly onto the business card. It is achieved by embedding a comprehensive business card within the QR code.
  • Inventory Management: QR codes aid in tracking products more accurately and precisely.
  • Apps: QR codes are leveraged to facilitate increased app downloads. A single scan allows users to download the application directly from either the Google Play Store or the App Store using QR codes.
  • Product Packaging: QR codes for products provide more comprehensive information about a product, presenting instructions in a broader and user-friendly manner.
  • Events: QR codes are employed throughout the event organization process, from delivering event information to customers and displaying advertisements during the event.
  • Social Media: QR codes are utilized to swiftly connect with individuals and link to social media accounts with just one scan, facilitating immediate access to multiple platforms.

How are QR code readers very convenient?

QR code readers are very convenient because they quickly scan a QR code in just a few seconds using the phone's camera. Most devices, particularly smartphones, come pre-equipped with QR code reader software, eliminating the need for a third-party application. The functionality applies to both iOS and Android devices. The scanning process itself is swift, taking only a few seconds. The convenience lies in the fact that the entire process takes place on the phone, which individuals typically carry. QR scanners read both printed and digital QR codes. No special tools are required to read the QR code. The QR code reader retrieves and interprets it successfully, regardless of the type of information contained within the QR code.

Does the QR code reader need infrared?

No, the QR code readers do not need infrared. QR codes comprise a pattern of white and black squares containing information. The remarkable aspect is that the codes are read using standard visible light, eliminating the necessity for infrared technology. Infrared technology is not a prevalent feature in most QR scanners. However, infrared technology enables scanning in low-light conditions, offering great convenience. Specific newer QR scanners incorporate the technology. However, QR code readers generally do not rely on or require infrared technology for their scanning capabilities.

Are there dangers of using QR code readers?

No, there are no dangers in using QR code readers. Readers decode information within QR codes, and their usage poses no inherent danger. However, it is essential to exercise caution as there are instances where malicious individuals use a QR code for nefarious purposes, resulting in adverse outcomes when scanned with a QR code reader. It is crucial to implement secure measures, making QR codes safe to protect user privacy and data integrity. The malicious QR codes often contain embedded links that direct users to hazardous websites. People often scan compromised QR codes when unsuspectingly directing themselves to these unsafe websites, putting their personal information at risk. Unfortunately, QR code readers do not indicate whether the information contained within a QR code is safe or dangerous.

QR code readers are software or applications that read QR codes using the cameras of phones, tablets, and computers. The QR code reader extracts the information stored within it by simply holding the device over it. QR codes contain patterns and error correction levels that enable the reader to decipher the QR code data quickly. Users access the information in QR codes within seconds with the help of QR code readers. However, exercising caution when using a QR code reader is crucial. It is essential to thoroughly analyze whether a QR code is dangerous before scanning it. QR code reader applications are downloaded for devices without built-in scanning capabilities. Most laptops, computers, and smartphones serve as QR code readers, providing the necessary functionality to scan and interpret QR codes.

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Content Manager

Ilaha Mammadova

As an experienced content manager, Ilaha specializes in crafting SEO-friendly content that blends creativity and strategy. With a passion for delivering high-quality, engaging content, Ilaha focuses on innovative ideas to help brands elevate their digital presence. Her dedication to excellence ensures that every piece ranks well and resonates with the target audience, making a lasting impact. In her free time, she enjoys singing a song and capturing moments through photography, adding an extra touch of creativity to everything she does.

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