# LinuxCNC G20

Instructions · `G20` · verification: source checked

G20 is a G-code instruction that selects inches for length units in a program. The manual recommends including unit selection in the preamble of each G-code file.

## Specification

| Property | Value |
|---|---|
| Language | gcode |
| Code | G20 |
| Group | Units |
| Dialect | LinuxCNC |

## Connected

- Related: [LinuxCNC M72](https://machineschema.com/instruction/mcode-m72.md)

## Study notes

- The manual recommends including units in the preamble of each G-code file.

## Sources

1. [G-Codes](https://linuxcnc.org/docs/html/gcode/g-code.html#gcode:g20-g21) (accessed 2026-10-26)

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Source page: https://machineschema.com/instruction/gcode-g20  
JSON: https://machineschema.com/instruction/gcode-g20.json  
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite Machine Schema and the original sources.