The basic formula for conversion from microinch to micron (micrometer):
| 1 microinch = 0.0254 micrometer |
| 1 micron = 39.4 microinches |
Some common finishes:
| 10 microinch Ra = .229 to .279 micron R |
| 15 microinch Ra = .381 micron Ra |
| 20 microinch Ra = .508 micron Ra |