| FEPA[1] | Average particle diameter (µm) | Historic British size |
|---|---|---|
| P2000 | 9.6 | 4/0 |
| P1500 | 12.3 | 3/0 |
| P1200 | 15.8 | 2/0 |
| P1000 | 18.3 | - |
| P800 | 21.8 | - |
| P600 | 25.8 | - |
| P500 | 30.2 | 0 |
| P400 | 35.0 | 1F |
| P360 | 40.5 | - |
| P320 | 46.2 | - |
| P280 | 52.5 | - |
| P240 | 58.6 | 1 |
| P220 | 68.0 | - |
| P180 | 82.0 | 1G |
| P150 | 100.0 | 2 |
1Federation of European Producers Association
Unlike modern standards, historic grades are not consistent. Sizes such as 2/0 and 3/0 may also be written as 00 and 000.
