Code 25 Specification

Standard 2 of 5 was invented in early 1960s. Since then it has been widely used in warehouse, photo finishing and airline industries. It is also called industry 2 of 5.

Standard 2 of 5 is a numeric symbology and its character set includes 10 digital characters: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

The symbology receives this name because every character is encoded with 5 bars where 2 bars are wide. Code25 only uses bar width to encode the data. Interleaved 2 of 5, however, uses both widths of bars and spaces.

A complete Standard 2 of 5 barcode must include a start character and a stop character. Optionally it ends with a modulo 10 check digit.

Standard 2 of 5 is a very simple and low density symbology. Its variant, Interleaved 2 of 5 (ITF25), has a slightly higher density.


  • Industry 2 of 5 – Identical to Standard 2 of 5.

  • Standard 2 of 5 Mod 10 – A modulo 10 check digit is appended to the barcode message to perform checking.

Structure of a Code25 symbol

A typical Code25 barcode has the following structure:

  • A start character

  • Message encoded

  • Optional Mod 10 check digit

  • A stop character

Check Digit Calculation

  1. Start with the right-most digit in the message; mark the character with even and odd position. The right-most digit has the even position.

  2. Sum all digits in the odd position.

  3. Sum all digits in the even position, and then multiply by 3.

  4. Add the result 2 and result 3.

  5. Divide the result of step 4 by 10, the check digit is the result equal to that 10 minus the remainder. In the case the the remainder is 0, the check digit is 0.