Are you looking for a Excel spreadsheet that you plug in AD&D stats and it gives you a 3x version?
or Are you looking for a Excel spreadsheet that will advance existing monsters, eather by HD or class?
Yeah Cleon
A long time ago when en world used to host game resources like module conversions there used to be a 3.0 spreadsheet that did almost all the math for you. Im trying to find something like that.