Conversion Charts

The charts below shows the conversion between imperial and metric measurements and the size in millimetres for the different screw sizes.

Imperial
Metric
1/4"
6.4mm
1/4"
6.4mm
5/6"
7.9mm
3/8"
9.5mm
7/16"
11.1mm
1/2"
12.7mm
5/8"
15.9mm
3/4"
19.1mm
7/8"
22.2mm
1"
25.4mm
1.1/4"
31.8mm
1.5/16"
33.3mm
1.3/8"
34.9mm
1.7/16"
36.5mm
1.1/2"
38.1mm
1.5/8"
41.3mm
1.3/4"
44.5mm
1.7/8"
47.6mm
2"
50.8mm
2.1/4"
57.2mm
2.5/16"
28.7mm
2.3/8"
60.3mm
2.7/16"
61.9mm
2.1/2"
63.5mm
2.5/8"
66.7mm
2.3/4"
69.9mm
2.7/8"
73.0mm
3"
76.2mm
3.1/4"
82.6mm
3.5/16"
84.1mm
3.3/8"
85.7mm
3.7/16"
87.3mm
3.1/2"
88.9mm
3.5/8"
92.1mm
3.3/4"
95.3mm
3.7/8"
98.4mm
4"
101.6mm


Screw Number
Size
Size No. 4
2.9mm
Size No. 6
3.5mm
Size No. 7
3.9mm
Size No. 8
4.2mm
Size No. 10
4.8mm
Size No. 12
5.5mm
Size No. 14
6.3mm