A request to all italians here

Thanks, but that doesn't help me at all. Large pizza for me is 20 inches = 50 cm
aka "family pizza". Normal would be 12 inches or 30 cm as I make them also. For
me they all look the same in size, because the plate is the same size always. Maybe
some are stretched a bit more to add more sauce and cheese. This is why I'm
asking italians or anyone with similar experience

Thanks a lot. Found english translation here .
I knew about this document a long time ago, and planning to get a hold
of similar stuff or regional pies, but a bit busy with multitasking here...

Yes, I know it's around 12-13 inches, that's the "normal" in US too. I was surprise to see different sizes.