QR Code Generator — Create QR Codes from Text or URLs

The Formula

A QR (Quick Response) code is a two-dimensional matrix barcode invented by Denso Wave in 1994. Data is encoded in black and white square modules arranged in a grid pattern. The structure includes finder patterns (the three large squares in corners for position detection), timing patterns for module alignment, format information, and the data area with error correction codewords using Reed-Solomon codes.

Variable Definitions

How to Use This Calculator

1. 1

   Enter the text, URL, or any content you want to encode in the QR code.

2. 2

   Adjust the pixel size (100px to 500px) to control the image resolution.

3. 3

   The QR code image is generated via the QR Server API and displayed in the panel below.

4. 4

   Use the download button to save the QR code as a PNG image file.

Quick Reference

Common Applications

• Sharing website URLs and landing pages in print media, posters, and business cards.
• Encoding WiFi credentials for quick network access without typing passwords.
• Storing contact information (vCard format) for easy mobile phone import.
• Providing product information, serial numbers, and authentication codes in manufacturing.
• Contactless payment and ticketing systems in retail and transportation.

QR code anatomy: finder patterns (position detection), timing patterns, data modules, and error correction codewords

Understanding the Concept

QR (Quick Response) codes are two-dimensional barcodes that can store significantly more data than traditional one-dimensional barcodes. A QR code encodes data using black modules arranged in a square grid on a white background, which can be read by cameras and image processing algorithms. The structure includes finder patterns (three identical squares in corners) that allow omnidirectional scanning, timing patterns that define module positions, alignment patterns for larger versions, format information, version information, and the actual data regions with error correction codewords. Reed-Solomon error correction is key to QR code reliability: even if a QR code is partially damaged, dirty, or obscured, the data can still be recovered. The four error correction levels (L, M, Q, H) allow users to trade data capacity for resilience. QR codes support four data modes: numeric (0-9), alphanumeric (0-9, A-Z, and some symbols), byte/binary (ISO-8859-1), and Kanji (Shift JIS). The maximum capacity depends on both version and error correction level: a Version 40 QR code with L-level correction can store up to 4,296 alphanumeric characters or 2,953 bytes.

Frequently Asked Questions

Sources & References