What is error correction in QR codes?

Created on 10 July, 2023FAQ • 1 minutes read

Error correction in QR codes refers to the built-in mechanism to enable data recovery if any part of the QR code is damaged or unreadable. This is made possible by including redundant data in the QR code so that the scanner can reconstruct the missing or damaged information.

There are four levels of error correction in QR codes, denoted by the letters L, M, Q and H:

  1. L (Low) - 7% of codewords can be recovered.
  2. M (Medium) - 15% of codewords can be recovered.
  3. Q (Quartile) - 25% of code words can be recovered.
  4. H (High) - 30% of code words can be recovered.

The higher the error correction level, the more redundant data is included in the QR code and the more resistant the code is to corruption. The disadvantage of increasing the error correction level is that the QR code becomes larger and more complex, requiring more storage space and possibly longer scanning time.

When choosing an error correction level, it is important to consider the environment and use of the QR code. For example, if the QR code will be used outdoors or is subject to wear and tear, it may be wise to choose a higher error correction level. For general use, the Q level is usually recommended, as it provides a good balance between error correction and size of the QR code.