Check Digit for International Standard Book Number

ISBN is a FORTRAN90 library which can compute the check digit for an International Standard Book Number (ISBN), or report whether a given ISBN is valid.


The computer code and data files made available on this web page are distributed under the GNU LGPL license.


ISBN is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.

Related Data and Programs:

LUHN, a FORTRAN90 program which computes the Luhn check digit for a string, and can validate a string.

UPC, a FORTRAN90 library which can determine the check digit for a Uniform Product Code (UPC) or report whether a given UPC is valid.


Source Code:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN90 source codes.

Last revised on 08 September 2015.