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How does a QR code work?

TechnologyLesson on requestFree to read

Quick answer

A QR code works by storing data as a grid of black and white squares that a camera reads as binary 1s and 0s. Special corner patterns let the scanner find and orient the code, then decode the pattern into text, a link, or other information.

Step by step

  1. Each black or white module represents a bit, so the grid encodes binary data.
  2. Three large corner squares let a scanner locate and align the code at any angle.
  3. Built-in error correction lets it still scan even if part is dirty or damaged.
  4. Software decodes the pattern into a URL, text, payment info, or Wi-Fi details.
  5. It holds far more than a 1D barcode because it stores information in two dimensions.

People also ask

Can a QR code still scan if it's partly damaged?
Often yes. QR codes include error correction that can rebuild up to about 30% of missing data, depending on the level used.
Why do QR codes have three big squares?
Those 'finder patterns' let the scanner instantly detect the code's position and orientation, so it reads correctly from any angle.
Are QR codes safe to scan?
The code itself is just data, but it can hide a malicious link — check the URL before opening, just as you would any link.
How does a phone read a QR code?
The camera captures the pattern, and software locates the alignment markers and decodes the squares into data.
What information can a QR code hold?
Usually a web link, but also text, contact details, Wi-Fi credentials, or payment info.
Why do QR codes still work when slightly damaged?
They include built-in error correction, so part of the code can be missing and still decode.