QR codes have become ubiquitous—on flyers, menus, business cards, and payments. But how exactly does a QR code translate data into a scannable pattern? Here's an intuitive breakdown of the process behind QR codes, step-by-step.

1. Choose Data

Everything begins with the data you want your QR code to carry. It could be:

• A URL linking to your website
• Contact details for a business card
• Payment information for transactions
• Plain text messages or instructions

The amount and type of data directly influence the complexity and size of the QR code you generate.

grid qr.grid

functional_grid qr.functional_grid

data_grid qr.data_grid

finder_grid qr.finder_grid

2. Binary Encoding

Once you have your data, the QR encoding process selects the most efficient way to represent it. QR codes support different encoding strategies, including:

• Numeric Mode: For digits (0-9)
• Alphanumeric Mode: For numbers, letters, and a limited set of special characters
• Byte Mode: For encoding general binary data, including UTF-8 encoded text
• Kanji Mode*: For efficient encoding of Japanese Kanji characters (not yet supported)

Your data type determines which mode is optimal. Typically, QR generators automatically pick the best encoding strategy to produce the smallest, most efficient QR code possible.

[placeholder: Graphic illustrating how different data types match with encoding modes]

3. Error Correction

One powerful feature of QR codes is their built-in error correction capability. Error correction ensures the QR code remains scannable even when partially obscured or damaged.

QR codes use the Reed-Solomon error correction algorithm, which creates additional redundant codewords. There are four levels of error correction available:

[Error Correction Table]

Higher error correction levels produce more robust QR codes but require more space, resulting in larger codes.

[placeholder: Visual demonstration showing how error correction helps QR remain readable even if partly damaged]

4. Draw to Grid

The final step involves mapping these binary codewords onto the QR code's characteristic grid of squares. The grid includes:

• Finder Patterns: Distinct squares at three corners for easy detection by scanners
• Alignment Patterns: Help scanners identify and correct distortions (present in larger QR codes)
• Timing Patterns: Assist in accurately aligning the scanning grid
• Data Modules: Actual bits of data and error-correction codewords

The data bits are carefully placed into a predefined layout, forming the distinctive visual pattern you're familiar with. Dark squares represent binary 1s, and light squares represent binary 0s.

[placeholder: Interactive graphic showing the step-by-step placement of binary data into QR modules]

5. Beautify