U.S. Code of Federal Regulations

Regulations most recently checked for updates: Sep 29, 2022

§ 51.1538 - Metric conversion table.
Inches Millimeters
(mm)
1/8 equals3.2
1/4 equals6.4
3/8 equals9.5
1/2 equals12.7
5/8 equals15.9
3/4 equals19.1
7/8 equals22.2
1 equals25.4
1 1/4 equals31.8
1 1/2 equals38.1
1 3/4 equals44.5
2 equals50.8
3 equals76.2
4 equals101.6