I would use that tool to estimate how you can get a given frame to have approximately the same reach & stack as your old frame. take the calculation with a grain of salt and know that you might have to tweak it with the stem position to get it just right. play around with the stem length, angle, and spacers to see what it would take to get the handlebar to the same "reach" and "stack" at the bar.
then consider the seat tube angle. unless the STA on two frames is identical, the saddle position you end up with might be a little different from your old one relative to the handlebar on your old setup.

in case you were basing your standover height comment on the graphic above, that's not the standover. that's the effective top tube. I love that bikegeo tool and use it all the time for bike thought experiments and the occasional purpose. I think it might have been possible to program it so it shows actual top tube, but on every bike, it shows a horizontal line of the ETT. the standover of those bikes might be vastly different.