Machinist unit converter
The conversions a drawing actually asks for, in one place. 25.4 µm to a thou; 0.8 µm Ra to ≈32 µin; 30°15′ to 30.25°; 350 SFM to 107 m/min. Covers length down to tenths, angles with degrees-minutes-seconds, temperature, pressure, torque, force, speed, mass, and roughness — with enough decimal places to matter at inspection tolerances.
- Converted value
- millimeter
- centimeter
- meter
- inch
- thou (mil, 0.001 in)
- tenth (0.0001 in)
- foot
How it’s calculated
Each conversion maps from the source unit to the group base unit, then from the base unit to the target unit; temperature uses affine offsets.
Which conversions does a drawing need?
Engineering drawings mix units freely — a diameter in millimetres, a finish in microinches, an angle in degrees-minutes-seconds, a torque spec in one system and your wrench in another. Converting them by hand invites a slipped decimal right where inspection tolerances are tightest, so this tool keeps the common machinist conversions in one place with enough precision to matter.
It covers length down to tenths, angle in decimal degrees and DMS, temperature, pressure, torque, force, speed (SFM↔m/min), mass, and surface roughness in µm and µin with the nearest ISO 1302 N grade. Pick a group, enter a value, and read the conversion — the default result renders before the page finishes loading, so the answer is there immediately.