penny size
length(inches)
length(nearest mm)
2d
1
25
3d
1¼
32
4d
1½
38
6d
2
51
7d
2¼
57
8d
2½
65
9d
2¾
70
10d
3
76
12d
3¼
83
16d
3½
89
20d
4
102
30d
4½
115
40d
5
127
50d
5½
140
60d
6
152
