A QR code is a type of two-dimensional barcode that can store a significant amount of information. Unlike traditional barcodes that store data in horizontal lines and can only be read from one direction, QR codes can store information both horizontally and vertically. This allows them to hold up to 7,089 numeric characters or 4,296 alphanumeric characters, compared to the 39 numeric characters of a standard barcode.

The Components of a QR Code

A QR code consists of several elements:

  1. Positioning Marks: These are the larger squares found in three corners of the code. They help the reader device understand the size, orientation, and angle of the QR code.
  2. Timing Patterns: These alternating black and white modules help the reader determine the size of the code.
  3. Format Information: This part includes error correction level and data mask pattern used.
  4. Version Information: For larger QR codes (versions 7 and up), this section indicates the size of the QR code.
  5. Data and Error Correction Codewords: This is where the actual data, along with error correction codes, are stored.

The Reading Process

Reading a QR code is a simple process that involves three key steps:

  1. Grid placement: The reader device identifies the three large squares, which allows it to understand the size, angle, and orientation of the QR code. It then places a grid over the code to read it.
  2. Binary Conversion: Each small square (module) in the QR code is translated into binary. Black squares represent 1, and white squares represent 0.
  3. Data Decoding: The binary data is then decoded using the ISO 18004 standard. The error correction codes help ensure that the data is read correctly, even if the QR code is partially damaged or obscured.

Creating Custom QR Codes

With the help of online tools, you can create your custom QR codes. These tools convert the data you enter—such as a URL, text, contact information, or Wi-Fi login—into a QR code image. You can then download this image and use it on your website, print materials, or anywhere else you wish to share this data.


Behind their simple appearance, QR codes are a marvel of digital encoding, packing a substantial amount of information into a small space. They offer a seamless, efficient, and interactive way for people to engage with digital content in the physical world. As the world continues to embrace contactless and digital technologies, the usage and relevance of QR codes are set to grow even further. Whether you're a business owner looking to streamline customer interactions or an individual eager to understand the digital world better, grasping how QR codes work offers useful insights into our interconnected reality.