QR Code Structure Simulator (2D)

Encode Text

Message (max 40 chars)

Error Correction

Ready — type a message and press Encode.

Live Readout

Module count

EC level

Data capacity used

0 / 0 bits (0%)

How it works

Every QR code carries three identical finder patterns (the bullseye squares) in three of its four corners. A scanner looks for these first — their fixed ratio of black-white-black-white-black is unmistakable at any rotation, so the camera instantly knows the code's position, scale and orientation without reading a single data bit.

The dashed timing patterns running between the finders (alternating black/white modules) tell the scanner exactly where each row and column of modules sits, so it can correct for lens distortion and camera angle before decoding.

Everything else is the data region: your message is converted to bits and threaded through the grid in a zigzag path, column pair by column pair, weaving around the finder and timing patterns. A portion of that region is reserved for error-correction code (Reed-Solomon in a real QR code) — the higher the EC level, the more of the grid is spent on redundancy instead of raw data, but the more scratches or smudges the code can survive.

Finder / timing Data (your message) Error correction