libdEdx provide libraries to calculate stopping power offline.

libdedx is written in C, and provides access to a variety of stopping power data, CSDA range calculations, inverse stopping power lookups, and requested energy for a given CSDA range. The library is available on sourceforge, and it is licensed under GNU GPL.

https://sourceforge.net/projects/libdedx/

At the moment the library is only available for Linux users. If there is interest for a Windows version it will be provided on demand.

Along with the library a simple command line program is shipped getdedx, which allows you to calculate stopping power directly.