Sorry, I don't do simple calculators. I just use Scubabatdan's because it does everything I need it to do and looks nicer than the one I made in Excel.
I don't shoot Glocks either, but that is because they don't fit my hands worth a bean. Now a S&W 1006 fits nice, but could be thicker...
So, it's a matter of finding what fits you. The above suggestions are great. Take them out to the range and run them
through a few times and see which one keeps you on target.
I'll be RSO at Roby's range tonight if you want to join us. (Range Safety Officer for the non-shooting folks. Expecting over a dozen scouts for further training tonight.)