QR QR Studio

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QR code anatomy explorer

Published 7 September 2026

  • Version 3, 29×29 modules, error correction M, mask 0. Tap a label to isolate it.

Runs entirely on your device. Nothing you enter or upload is sent to a server.

Reading the colours

  • Finder patterns (purple): the three big squares. They tell the scanner where the code is and which way up.
  • Separators: a one-module white border around each finder.
  • Timing patterns (orange): alternating dark and light between the finders, so the scanner can count modules.
  • Alignment patterns (green): small squares that let the scanner correct for a curved or tilted surface. Version 1 has none; larger versions have many.
  • Format information (red): 15 bits, stored twice, giving the error-correction level and the mask.
  • Version information (teal): from version 7 upwards, 18 bits saying which version this is.
  • Data (black and white): your content plus error-correction codewords.

Try it yourself

Now that you can see the parts, the explainer walks through what the scanner does with each of them.

How a QR code works

Frequently asked questions

What is the mask pattern?

One of eight XOR patterns applied to the data area so that no large blank or dark regions form, and so it never resembles a finder pattern. The encoder tries all eight and picks the one with the lowest penalty score.

Why is there a lone dark module near the bottom-left finder?

It is always dark, by specification. Decoders use it as a reference. It sits beside the format information.

Where is my actual text?

In the white and black modules labelled data, read in a zigzag from the bottom-right corner upwards, two columns at a time.

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