COMMON PREPARATORY CODES
CNC G-Code Guide
A practical overview of common CNC G codes for motion, planes, units, work offsets, compensation and drilling cycles.
CNC G Codes
G codes define preparatory functions such as axis motion, plane selection, units, coordinate modes and machining cycles. The exact behavior and available options depend on the control, machine configuration and active parameters.
Common motion and setup codes
G00 rapid positioning · G01 linear feed · G02/G03 circular interpolation · G17/G18/G19 plane selection · G20/G21 inch or millimetre units · G54–G59 work coordinate systems · G90/G91 absolute or incremental mode.
Compensation and drilling cycles
G40 cancels cutter-radius compensation; G41/G42 select left/right compensation where supported. G43/G49 manage tool-length compensation on many milling controls. G80 cancels fixed cycles; G81 is a common drilling cycle and G83 a common peck-drilling cycle.