I made a small python program with a GUI to compute (from analytical formulas), the stray field produced by the cycloidal order in BiFeO3. And I called it the BFO-ator. You can find the python scripts on github, as well as the manual.
Alternatively, I made a .exe file for Windows, but the file is quite big. You can download it from here, slow connection, it is faster to install python, or here, much faster, but this link will die at some point in the future.