How do I calculate the Mod 10 check digit or the necessary Check Digit for a given code?
More information about calculating a Mod 10 check digit can be found at the bottom of the Interleaved 2 of 5 Page. Please note that each barcode symbology that uses a modulo check digit has a method defined by its specification. Code 39 does not normally need a check digit, but there is a check digit system defined in the specification. See the Code 39 specification page. Code 128 uses Mod 103.
