G-code

G-code is a language in which people tell computerized machine tools how to make something. The "how" is defined by g-code instructions provided to a machine controller (industrial computer) that tells the motors where to move, how fast to move, and what path to follow. The most common situation is that, within a machine tool, a cutting tool is moved according to these instructions through a toolpath and cuts away material to leave only the finished work-piece. Industry has standardized on G-Code as its basic set of CNC machine codes. G-Code is the most popular programming language used for programming CNC machinery. Some G words alter the state of the machine so that it changes from cutting straight lines to cutting arcs. Other G words cause the interpretation of numbers as millimeters rather than inches. Some G words set or remove tool length or diameter offsets. Below is a complete listing of G-codes. 

G-Code	Description
G00	Rapid Linear Interpolation
G01	Linear Interpolation
G02	Clockwise Circular Interpolation
G03	Counter Clockwise Circular Interpolation
G04	Dwell
G05	High Speed Machining Mode
G10	Offset Input by Program
G12	Clockwise Circle with Entrance and Exit Arcs
G13	Counter Clockwise Circle with Entrance and Exit Arcs
G17	X-Y Plane Selection
G18	Z-X Plane Selection
G19	Y-Z Plane Selection
G28	Return to Reference Point
G34	Special Fixed Cycle (Bolt Hole Circle)
G35	Special Fixed Cycle (Line at Angle)
G36	Special Fixed Cycle (Arc)
G37	Special Fixed Cycle (Grid)
G40	Tool Radius Compensation Cancel
G41	Tool Radius Compensation Left
G42	Tool Radius Compensation Right
G43	Tool Length Compensation
G44	Tool Length Compensation Cancel
G45	Tool Offset Increase
G46	Tool Offset Decrease
G50.1	Programmed Mirror Image Cancel
G51.1	Programmed Mirror Image On
G52	Local Coordinate Setting
G54 - G59	Work Coordinate Registers 1 Thru 6
G60	Unidirectional Positioning
G61	Exact Stop Check Mode
G65	Macro Call (Non-Modal)
G66	Macro Call (Modal)
G68	Programmed Coordinate Rotation
G69	Coordinate Rotation Cancel
G73	Fixed Cycle (Step)
G74	Fixed Cycle (Reverse Tapping)
G76	Fixed Cycle (Fine Boring)
G80	Fixed Cycle Cancel
G81	Fixed Cycle (Drilling / Spot Drilling)
G82	Fixed Cycle (Drilling / Counter Boring)
G83	Fixed Cycle (Deep Hole Drilling)
G84	Fixed Cycle (Tapping)
G85	Fixed Cycle (Boring)
G86	Fixed Cycle (Boring)
G87	Fixed Cycle (Back Boring)
G88	Fixed Cycle (Boring)
G89	Fixed Cycle (Boring)
G90	Absolute Value Command
G91	Incremental Value Command
G92	Work Offset Set
G101	User macro 1 (substitution) =
G102	User macro 1 (addition) +
G103	User macro 1 (subtraction) -
G104	User macro 1 (multiplication) *
G105	User macro 1 (division) /
G106	User macro 1 (square root)
G107	User macro 1 (sine) sin
G108	User macro 1 (cosine) cos
G109	User macro 1 (arc tangent) tan
G110	User macro (square root)
G200	User macro 1 (unconditional branch)
G201	User macro 1 (zero condition branch)
G202	User macro (negative condition branch)