Scroll down for the metric/S.A.E. interlace table.

Distance:
 
 
 
    approximate
 
 
 
 
 
    use on land
    use at sea
 
 
 
 
 
    in free space

Which wrench/socket comes next in the other set?
Metric
mm 		S.A.E.
inch
4,5,6
1/4
7
5/16
8,9
3/8
10,11
7/16
12
Metric
mm 		S.A.E.
inch
1/2
13,14
9/16
15
5/8
16,17
11/16
18,19
3/4
Metric
mm 		S.A.E.
inch
20
13/16
21,22
7/8
23
15/16
24,25
1
26
Metric
mm 		S.A.E.
inch
1 1/16
27,28
1 1/8
29,30
1 3/16
31
1 1/4
32,33
1 5/16