A QR code (Quick Response code) is a two-dimensional barcode invented in 1994 by the Japanese company Denso Wave. Unlike traditional one-dimensional barcodes that store data in a single row of varying-width lines, QR codes encode information in both horizontal and vertical directions using a matrix of black and white squares. This allows them to store significantly more data -- up to 4,296 alphanumeric characters or 7,089 numeric digits -- while remaining scannable by smartphone cameras. QR codes also include built-in error correction using Reed-Solomon algorithms, meaning they can still be read even if up to 30% of the code is damaged or obscured.
A QR code consists of several functional areas: finder patterns (the three large squares in the corners) help scanners locate and orient the code; alignment patterns assist with reading at an angle; timing patterns establish the grid coordinates; and the data area encodes the actual information along with error correction codewords. The encoding process converts your input text into a binary stream, applies error correction, and arranges the bits into the matrix according to a masking pattern that optimizes readability. Modern smartphones can decode QR codes instantly using their built-in camera apps, with no special software required.
QR codes are used everywhere: sharing website URLs on printed materials, encoding WiFi network credentials for easy connection, storing contact information in vCard format, enabling mobile payments, linking to app downloads, displaying event tickets, and providing product information on packaging. Businesses use them for restaurant menus, marketing campaigns, inventory tracking, and two-factor authentication setup. Our QR code generator lets you create downloadable PNG images at multiple sizes, perfect for embedding in documents, printing on business cards, or displaying on websites and presentations.