Complete G-Code & M-Code Reference for CNC Programmers and Operators

Discover the full list of standard G-codes and M-codes used in CNC programming. Includes real-world examples, usage explanations, and downloadable G-code charts. Perfect for beginners and professionals.

G-Code (geometric code) and M-Code (machine code) are the fundamental languages of CNC machining. Whether you’re programming a mill, lathe, or router, understanding these codes is critical. Below is a detailed reference guide to help you understand how each code works, what it does, and how to apply it correctly in your CNC programs.

📋 G-Code Command List (ISO Standard)

G-Code	Description	Example
G00	Rapid Positioning	G00 X0 Y0 Z0
G01	Linear Interpolation	G01 X50 Y50 F100
G02	Circular Interpolation CW	G02 X30 Y30 I10 J0
G03	Circular Interpolation CCW	G03 X10 Y10 I-5 J5
G17/G18/G19	Plane Selection (XY/XZ/YZ)	G17
G20/G21	Inch/MM Mode	G21 ; Metric
G28	Return to Machine Zero	G28 X0 Y0
G40/G41/G42	Tool Radius Compensation	G41 D1
G43	Tool Length Compensation	G43 H05
G80–G89	Canned Cycles	G81 ; Drilling

🛠️ G-Code Example: Hole Drilling Cycle

G90 G21           ; Absolute, metric
G17 G40 G80       ; XY plane, cancel comp/cycle
T01 M06           ; Tool change
G00 X10 Y10       ; Position
G43 H01 Z5.0      ; Tool length offset
M03 S1200         ; Spindle on
G81 R2 Z-10 F200  ; Drilling cycle
G80               ; Cancel cycle
G00 Z50           ; Retract
M05               ; Spindle stop
M30               ; End of program

⚙️ M-Code Command List (Fanuc/Haas Style)

M-Code	Description	Example
M00	Program Stop	M00
M01	Optional Stop	M01
M03/M04	Spindle On (CW/CCW)	M03 S1500
M05	Spindle Stop	M05
M06	Tool Change	T2 M06
M08/M09	Coolant On/Off	M08
M30	End of Program	M30

📈 High-TBM Keywords for SEO

• G-code cheat sheet PDF
• M-code list Fanuc CNC
• tool change G-code tutorial
• how to use G43 H offset
• G02 vs G03 explained

📄 G-Code Troubleshooting Table

Issue	Cause	Solution
Tool crashes into workpiece	G43/H offset missing	Use G43 Hxx before Z move
Circular arc error	Missing I/J values	Double check arc center offsets
Alarm 017: Invalid G-code	Unsupported G-code	Refer to machine G-code list

📥 Downloadable G-Code Chart

Offer a free downloadable PDF G-code chart covering over 100 commands with syntax, usage, and machine-specific tips. Great for shop floor printout or student reference.

✅ Conclusion

Mastering G-code and M-code is a foundational skill in CNC machining. Whether you’re fine-tuning a complex program or writing basic tool paths, this reference is an essential resource. cnccode.com provides industrial-grade content for CNC operators, educators, and professionals worldwide — with real code, verified examples, and practical applications.