Assuming you're talking about the inner hub print diameters. A ruler is helpful for measuring.
They tend to be pretty standard, but different printers will align differently. So one printer may do better with 22mm on a given disc where another may need 21mm.
Anyway, here's what I have: (These are for Canon printers)
TY Watershield, plain white and TY CDR, hub: 23x118
TY Silver: 44x117
TY Silver, hub: 26x118
TY Silver Watershield CDR, hub: 23x117
Verbatim DL DVD: 36x118
Verbatim Gloss: 38x118
Verbatim AquaAce: 21x118