G-code List for CNC [Complete List]

G-code is a series of preparatory commands used to control CNC machines. It can be programmed manually or using software programs.

G-codes Used on CNC Mills

The following is a list of G-codes used to program CNC mills and machining centers.

G code	Function
G00	Rapid positioning
G01	Linear interpolation
G02	Clockwise circular interpolation
G03	Anticlockwise circular interpolation
G04	Dwell or Pause (used in a separate block)
G09	Exact stop (for stopping the axes)
G10	Setting programmable input data
G11	Canceling data setting mode
G15	Canceling polar coordinate command
G16	Interpretspolar coordinate command
G17	Commands designated to the XY plane
G18	Commands designated to the ZX plane
G19	Commands designated to the YZ plane
G20	Imperial/English units of input
G21	Metric units of input
G22	Turns on stored stroke check
G23	Turns off the stored stroke check
G25	Turns on spindle speed fluctuation detection
G26	Turns off spindle speed fluctuation detection
G27	Checks the machine’s zero position
G28	Machine returns to its zero position (point A)
G29	The machine returns to point A, then to the location specified on G29
G30	The machine returns to point A, then to a zero position (point B)
G31	Skip function
G40	Cancels the cutter radius compensation
G41	Compensates the left cutter radius
G42	Compensates the right cutter radius
G43	Compensates for a positive tool length
G44	Compensates for a negative tool length
G45	Position compensation – single increase
G46	Position compensation – single decrease
G47	Position compensation – double increase
G48	Position compensation – double decrease
G49	Cancels the tool length offset
G50	Cancels the scaling function
G51	Scaling function
G52	Switches to a local/child zero position
G53	Switches to the machine’s default zero position
G54	Work coordinate offset I
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	Positions the machine in a single direction
G61	Stops the machine
G62	Modal automatic corner override
G63	Tapping mode
G64	Cutting mode
G65	Calling custom macro commands (one time)
G66	Calling custom macro commands (on every machine movement)
G67	Cancels custom macro call commands
G68	Rotates the coordinate system at an angle
G69	Cancels the coordinate system rotation
G73	Peck and canned drilling cycles
G74	Left-hand rigid tapping or threading cycle
G76	Fine boring cycle
G80	Cancels active canned cycles
G81	Drilling cycle
G82	Dwell drilling cycle
G83	Deep hole peck-drilling cycle
G84	Right-hand rigid tapping or threading cycle
G85	Reaming cycle
G86	Boring cycle
G87	Back boring cycle
G88	Boring and dwelling cycle
G89	Back boring and dwelling cycle
G90	Absolute dimensioning mode
G91	Incremental dimensioning mode
G92	Setting an offset on the coordinatesystem
G98	The tool returns to the initial position
G99	The tool returns to the R plane in a fixed cycle

M-codes Used on CNC Mills

In a typical CNC program, G-codes and M-codes are used in combination. M-code controls the machine functions like the spindle on/off, tool change, coolant on/off, etc.

Following are some of the M-codes associated with programming CNC mills.

G-code Used on CNC Lathes

Since CNC lathes have a unique machining setup, they are programmed using certain lathe-specific codes.

In a CNC program, these lathe-specific G-codes are used with other general G-codes to complete the program.

G32 is an example of one such lathe-specific G-code that is used to execute a CNC threading cycle.

It takes in the input from the CNC operator and removes material to produce different types of threads like circular threads, acme threads, etc.

Following is a list of G-codes used to program CNC Lathes.

G-code	Function
G00	Rapid positioning
G01	Linear interpolation
G02	Clockwise circular interpolation
G03	Anticlockwise circular interpolation
G04	Dwell or Pause (used in a separate block)
G09	Exact stop (for stopping the axes)
G10	Setting programmable input data
G11	Data Setting mode cancel
G20	Imperial/English units of input
G21	Metric units of input
G22	Turns on stored stroke check
G23	Turns off the stored stroke check
G25	Turns on spindle speed fluctuation detection
G26	Turns off spindle speed fluctuation detection
G27	Checks the machine’s zero position
G28	Machine returns to its zero position (point A)
G29	The machine returns to point A, then to the location specified on G29
G30	The machine returns to point A, then to a zero position (point B)
G31	Skip function
G32	To cut screw threads
G35	Clockwise circular threading cycle
G36	Counterclockwise circular threading cycle
G40	Cancels the cutter radius compensation
G41	Compensates the left cutter radius
G42	Compensates the right cutter radius
G50	Position register, Set spindle speed range
G52	Switches to a local/child zero position
G53	Switches to the machine’s default zero position
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
G61	Stops the machine
G62	Modal automatic corner override
G64	Cutting mode
G65	Calling custom macro commands (one time)
G66	Calling custom macro commands (on every machine movement)
G67	Cancels custom macro call commands
G68	Rotates all axes to a specific angle
G69	Cancels G68 comand rotation
G70	Finishing cycle
G71	Rough turning cycle along the Z-axis direction
G72	Rough turning cycle along the X-axis direction
G73	Pattern repetition cycle
G74	Drilling cycle
G75	Grooving cycle
G76	Threading cycle
G90	Cutting cycle A (Group type A)
G90	Absolute positioning command (Group type B)
G91	Incremental positioning command (Group type B)
G92	Thread cutting cycle (Group type A)
G92	Registers tool position (Group type B)
G94	Cutting cycle B (Group type A)
G94	Feedrate per minute (Group type B)
G95	Feedrate per revolution (Group type B)
G96	Constant surface speed (CSS) cutting mode
G97	Cancels G96 command
G98	Feedrate per minute (Group type A)
G99	Feedrate per revolution (Group type A)

M-codes Used on CNC Lathes

M-Code	Function
M00	Compulsory program stop
M01	Optional program stop
M02	End of the program (can end with reset, but no rewind)
M03	Spindle rotation (normal)
M04	Spindle rotation (reverse)
M05	Spindle stop
M07	Turns on the coolant mist
M08	Coolant ON (turns on the coolant pump)
M09	Coolant OFF (turns off the coolant pump)
M10	Chuck jaw open
M11	Chuck jaw close
M12	Quill moves toward the tailstock
M13	Quill moves out of the tailstock
M17	Forward turret indexing
M18	Reverse turret indexing
M19	Spindle orientation
M21	Tailstock move forward
M22	Tailstock move backward
M23	Gradually pull out of the thread
M24	Turns off thread gradual pull-out
M30	The program ends with reset and rewind
M41	Selects a low-gear transmission
M42	Selects a gear higher than on M41 (if any)
M43	Selects a gear higher than on M42 (if any)
M44	Selects a high-gear transmission
M48	Turning off the feed rate override cancel
M49	Turning on the feed rate override cancel
M98	Subprogram call
M99	Subprogram end

List of Letter Blocks on G-code

Letters and numbers are the building blocks of a G-code program. So far, I’ve only listed the popular number blocks. Now I’ll introduce the letter blocks.

G and M are the most used letters in a G-code program. This is because the letter G is used to call out the general functions, and M is used to call the miscellaneous/machine functions.

Following are the other letter blocks used in a G-code program.

Letter	Denotes
A	Machine’s A-axis
B	Machine’s B-axis
C	Machine’s C-axis
D	Diameter/radius compensation for tool
E	Precise feed rate (used on lathes for threading operations)
F	Feed rate
H	Cutter length
I	Center of an arc along the X-axis Also in G87 as X offset
J	Center of an arc along the Y-axis Also in G87 as Y offset
K	Center of an arc along the Z-axis Also in G87 as Z offset
L	No. of loop repetitions To specify the register that needed to be edited using G10
N	Program line/block number
O	Naming the program
P	Parameter address forG-codes and M-codes
Q	Feed increment in canned cycle
R	Radius of arc Retract length in canned cycle
S	Spindle speed
T	Tool selection
U	Associated with A-codes
V	Associated with B-codes
W	Associated with C-codes
X	Machine’s X-axis
Y	Machine’s Y-axis
Z	Machine’s Z-axis

List of G-code Commands

Command	G-codes
Non-modal	G04, G09, G10, G11, G27, G28, G29, G30, G31, G37, G45, G46, G47, G48, G50, G51, G52, G53, G60, G60, G70, G71, G72, G73, G74, G75, G76, G92
Motion	G00, G01, G02, G03
Cutting	G32, G35, G36, G90, G92, G94
Feed rate	G93, G94, G95
Polar input	G15, G16
Plane selection	G17, G18, G19
Dimensioning	G90, G91
Stored strokes	G22, G23
Unit input	G20, G21
Cutter radius offset	G40, G41, G42
Tool length offset	G43, G44, G49
Cycles	G73, G74, G76, G80, G81, G82, G83, G84, G85, G86, G87, G88, G89
Return	G98, G99
Canceling scaling	G50
Image mirroring	G68, G69
Coordinate system	G54, G55, G56, G57, G58, G59
Coordinate rotation	G68, GG69
Cutting mode	G61, G62, G63, G64
Macro mode	G66, G67
Constant Surface Speed	G96, G97
Spindle speed fluctuation	G25, G26

These G-code commands are used for milling and turning applications, but some of them are job specific.

For example, the polar input, tool length offset, coordinate rotation, return, and plane selection commands are only used for milling jobs.

Whereas in the case of programming lathes, constant surface speed, mirror image, and cutting cycles are some of the lathe-specific commands.

Frequently Asked Questions

What is CNC programming?

CNC programming is the process of automating the machining process of a CNC machine by writing a CNC program using G-code. This task is usually performed by a CNC machinist.

Is learning G-code easy?

Yes,learning G-codeis easy if you understand its structure and its building blocks. A G-code program is a command to the CNC machine directing it to perform specific tasks. If you can understand the purpose of each building block, then you can easily learn CNC programming.

How is the G-code program generated?

The G-code programs are generated using CAM (Computer-Aided Manufacturing) software programs. This software analyses geometrical data from design files and generates program code for specific machines to manufacture the part.

G-code List for CNC [Complete List] - MellowPine (2024)