Metric

mm inches
1 0.0394
2 0.0787
3 0.1181 1/8“
4 0.1575
5 0.1969
6 0.2362 1/4”
7 0.2756
8 0.315
9 0.3543 3/8“
10 0.3937
11 0.4331
12 0.4724
13 0.5118 1/2”
14 0.5512
15 0.5906
16 0.6299 5/8“
17 0.6693
18 0.7087
19 0.748 3/4”
20 0.7874
21 0.8268
22 0.8661 7/8“
23 0.9055
24 0.9449
25 0.9843
26 1.0236 1”
SAE SizeApproximate Diameter (inches)Approximate Diameter (mm)Closest Metric EquivalentMetric Major Diameter (mm)
0 0.060 1.524 M1.6 1.6
1 0.073 1.854 M1.8 1.8
2 0.086 2.184 M2 2.0
3 0.099 2.515 M2.5 2.5
4 0.112 2.845 M2.5 or M3 2.5 or 3.0
5 0.125 3.175 M3 3.0
6 0.138 3.505 M3.5 3.5
8 0.164 4.166 M4 4.0
10 0.190 4.826 M5 5.0
12 0.216 5.486 M5 or M6 5.0 or 6.0
1/4“ 0.250 6.350 M6 6.0
5/16” 0.3125 7.938 M8 8.0
3/8“ 0.375 9.525 M10 10.0
7/16” 0.4375 11.113 M10 or M12 10.0 or 12.0
1/2“ 0.500 12.700 M12 12.0
9/16” 0.5625 14.288 M14 14.0
5/8“ 0.625 15.875 M16 16.0
3/4” 0.750 19.050 M20 20.0
7/8“ 0.875 22.225 M22 22.0
1” 1.000 25.400 M24 or M25 24.0 or 25.0
Metric Size Major Diameter (mm) Major Diameter (inches)
M1.6 1.6 0.063
M1.8 1.8 0.0709
M2 2 0.0787
M2.2 2.2 0.0866
M2.5 2.5 0.0984
M3 3 0.1181
M3.5 3.5 0.1378
M4 4 0.1575
M4.5 4.5 0.1772
M5 5 0.1969
M6 6 0.2362
M7 7 0.2756
M8 8 0.315
M10 10 0.3937
M12 12 0.4724