Desi, probably you don't need it at all.

A linear transposer calculates transposed note names (also of chords) and / or positions of capos (transposing devices for guitars and similar instruments).

Circles of fifths sometimes serve the same purpose, whence the connection. More importantly, they are used to visualize harmonic relationships, since the main harmonic functions, to wit tonic, dominant, and subdominant, of a key are neighbours there.