Eleiko (and probably all other calibrated comp plates) are the following dimensions
Wt DIAMETER THICKNESS
25 kg 450 mm 25 mm
20 kg 450 mm 23 mm
15 kg 400 mm 21 mm
10 kg 325 mm 21 mm
5 kg 228 mm 21 mm
2,5 kg 190 mm 16 mm
1,25 kg 160 mm 12 mm
0,5 kg 134 mm 8 mm
0,25 kg 112 mm 6,5 mm