How QR Codes Work

QR codes may look simple, but they use advanced encoding and error-correction techniques to store and transmit data quickly and reliably.

Step 1: Data Encoding

When you create a QR code, the input data (URL, text, phone number, etc.) is converted into binary format. The data is then encoded into a square matrix of black and white modules. URL QR Code Generator

• Different encoding modes (numeric, alphanumeric, byte)
• Data is compressed to save space
• Structured into rows and columns

Step 2: Error Correction

QR codes use Reed–Solomon error correction, allowing them to be scanned even if part of the code is damaged or hidden.

Error correction levels include:

• L – ~7% damage recovery
• M – ~15% damage recovery
• Q – ~25% damage recovery
• H – ~30% damage recovery

Step 3: QR Code Structure

A QR code contains special patterns that help scanners read it correctly:

• Finder patterns – three large squares at the corners
• Alignment patterns – correct distortion
• Timing patterns – determine module size
• Quiet zone – white border around the QR code

Step 4: Scanning Process

When a smartphone camera scans a QR code, it detects the finder patterns, aligns the grid, and decodes the data into readable information.

1. Camera detects square patterns
2. Image is converted to binary
3. Error correction is applied
4. Decoded data is displayed instantly

Why QR Codes Scan So Fast

QR codes are optimized for speed. Their 2D structure allows scanners to read data both horizontally and vertically, unlike traditional barcodes.

Static vs Dynamic QR Codes

The working principle remains the same, but data handling differs:

• Static QR Codes store fixed data
• Dynamic QR Codes redirect to editable content

Read more: Static vs Dynamic QR Codes

Try It Yourself

See how QR codes work in real time by creating one instantly.