MSI Code

What is a MSI Code?

MSI Code is a variant of the Plessey Code, also known as Modified Plessey. The MSI Data Corporation developed the MSI Code to improve the decoding accuracy of the Plessey Code, which is one of the most error-prone barcodes.

A MSI Code only contains digits from 0 to 9. There are four possible check digit calculation algorithms for error detection:

  • Modulo 10
  • Modulo 11
  • Modulo 1010
  • Modulo 1110

By default, a Modulo 10 check digit is verified.

A typical MSI Code looks like this:

MSI Code

Where is a MSI Code used?

MSI Codes are used in inventory management to mark shelves and containers to identify storage locations.


  • Inventory
  • Warehousing