G-Codes List for CNC Machine Programming

G-codes are preparatory commands used in CNC programs. They set the machine control to a particular mode or operation. A CNC machinist must understand when to use each command to produce a part efficiently.

The following G-codes are used on many modern CNC milling machines:

• G00 – Rapid positioning
• G01 – Linear interpolation
• G02 – Clockwise circular interpolation
• G03 – Counterclockwise circular interpolation
• G04 – Dwell; use as a separate block
• G05 – High-speed machining or look-ahead on Fanuc controls
• G09 – Exact-stop check for one block
• G10 – Programmable data input or data setting
• G11 – Cancel data-setting mode
• G15 – Cancel polar-coordinate command
• G16 – Polar-coordinate command
• G17 – Select the XY plane
• G18 – Select the ZX plane
• G19 – Select the YZ plane
• G20 – Input in imperial units
• G21 – Input in metric units
• G22 – Stored-stroke check on
• G23 – Stored-stroke check off
• G25 – Spindle-speed fluctuation detection on
• G26 – Spindle-speed fluctuation detection off
• G27 – Machine-zero position check
• G28 – Return to machine zero or reference point 1
• G29 – Return from machine zero
• G30 – Return to machine zero or reference point 2
• G31 – Skip function
• G40 – Cancel cutter-radius compensation
• G41 – Cutter-radius compensation left
• G42 – Cutter-radius compensation right
• G43 – Positive tool-length compensation
• G44 – Negative tool-length compensation
• G45 – Position compensation, single increase
• G46 – Position compensation, single decrease
• G47 – Position compensation, double increase
• G48 – Position compensation, double decrease
• G49 – Cancel tool-length offset
• G50 – Cancel scaling
• G51 – Scaling
• G52 – Set a local coordinate system
• G53 – Machine coordinate system
• G54 – Work-coordinate offset 1
• G55 – Work-coordinate offset 2
• G56 – Work-coordinate offset 3
• G57 – Work-coordinate offset 4
• G58 – Work-coordinate offset 5
• G59 – Work-coordinate offset 6
• G60 – Single-direction positioning
• G61 – Exact-stop mode
• G62 – Automatic corner-override mode
• G63 – Tapping mode
• G64 – Cutting mode
• G65 – Custom macro call
• G66 – Modal custom macro call
• G67 – Cancel modal custom macro call
• G68 – Coordinate-system rotation
• G69 – Cancel coordinate-system rotation
• G73 – High-speed peck-drilling cycle for deep holes
• G74 – Left-hand threading cycle
• G76 – Fine-boring cycle
• G80 – Cancel fixed cycle
• G81 – Drilling cycle
• G82 – Spot-drilling cycle
• G83 – Peck-drilling cycle for deep holes
• G84 – Right-hand threading cycle
• G85 – Boring cycle
• G86 – Boring cycle
• G87 – Back-boring cycle
• G88 – Boring cycle
• G89 – Boring cycle
• G90 – Absolute-dimensioning mode
• G91 – Incremental-dimensioning mode
• G92 – Tool-position register
• G98 – Return to the initial level during a fixed cycle
• G99 – Return to the R-level during a fixed cycle

Using Multiple G-Codes

Two compatible G-codes may appear in the same program block. For example, G00 and G90 can be combined to move rapidly to a position using absolute coordinates.

G-code behavior and availability vary by controller and machine. Always confirm commands against the programming manual for the specific CNC machine before running a program.