No rounded intermediate steps.
Defined constants such as 1 inch = exactly 25.4 mm and 1 pound = exactly 0.45359237 kg are retained at full precision. Rounding happens only when the result is displayed.
WORKSHOP QUICK REFERENCE
Engineering Unit
Converter.
Convert the engineering units that matter beside a machine, at the bench or while checking a drawing—without hunting through a generic converter.
Start converting ↓01 · CONVERT
Engineering units.
Result1in
25.4 mm → 1 in
The international inch is exactly 25.4 mm.
ENGINEERING CATEGORIES
The units workshops use.
Choose a category to load compatible units. Force, mass and torque remain separate, and US and Imperial liquid measures are always identified.
CNC & MACHINING
Fast machine-side conversions.
Metric and imperial machining units stay separate from general velocity and dimensional categories, so the intended quantity is always clear.
Common Ra reference values
Ra is converted only between micrometres and microinches. It is not presented as a direct conversion to Rz.
ACCURACY & SAFE USE
Exact first. Rounded last.
116 unit entries across 24 compatible conversion groups are held in a separate structured registry so more engineering categories can be added cleanly.
Offsets handled properly.
Celsius, Fahrenheit and Kelvin use their correct affine transformations. They are not treated as ordinary multiplication-only units.
Similar names stay separate.
Pound mass is not pound-force. Mechanical hp is not metric PS. US gallons and GPM remain visibly separate from Imperial gallons and GPM.
No account required.
Favourites and recent conversions stay in the browser on the current device. Shared URLs carry only the selected units and value.
Primary metrology references
Conversion constants and engineering unit definitions are based on recognised SI and NIST guidance. Where variants exist, the specific standard is named in the unit label.
Engineering reference
Confirm safety-critical, regulated, calibration or contractual calculations against the governing drawing, specification or current standard. The converter does not replace certified measurement or engineering judgement.
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