CNC G-Code & M-Code Comparison Across Fanuc, Haas, Siemens, Heidenhain & Mazak

CNC programming varies significantly across different machine brands. While G-codes and M-codes serve similar purposes, their implementation and syntax may differ between controllers like Fanuc, Haas, Siemens, Heidenhain, and Mazak (Mazatrol).

This guide compares the most important G/M codes across all major platforms — helping CNC programmers avoid errors and streamline cross-machine setups.

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🧾 Full G-Code & M-Code Comparison Table

Function	Fanuc	Haas	Siemens	Heidenhain	Mazak (Mazatrol)
Rapid Positioning	G00	G00	G00	G00	G00
Linear Interpolation	G01	G01	G01	G01	G01
CW Arc (Circle)	G02	G02	G02	G02	G02
CCW Arc	G03	G03	G03	G03	G03
Dwell (Pause)	G04 P#	G04 P#	G04 P#	G04 P#	G04 P#
Tool Length Compensation +	G43	G43	G43	L… R…	T-code system
Tool Length Compensation –	G44	G44	G44	L… R…	T-code system
Cancel Tool Length Comp.	G49	G49	G49	G49	T-code system
Cutter Compensation Left	G41	G41	G41	L…	T-code system
Cutter Compensation Right	G42	G42	G42	L…	T-code system
Cancel Cutter Comp.	G40	G40	G40	G40	T-code system
Drilling Cycle	G81	G81	CYCLE81	CYCL DEF 200	G81
Peck Drilling	G83	G83	CYCLE83	CYCL DEF 201	G83
Tapping Cycle	G84	G84	CYCLE84	CYCL DEF 207	G84
Return to Zero (Home)	G28	G28	G28	L Z0	G28
Program End	M30	M30	M30	M30	M30
Spindle CW On	M03	M03	M03	M03	M03
Spindle CCW On	M04	M04	M04	M04	M04
Spindle Off	M05	M05	M05	M05	M05
Coolant On	M08	M08	M08	M08	M08
Coolant Off	M09	M09	M09	M09	M09
Tool Change	M06	M06	M06	TOOL DEF + CALL	M06 (T-code)
Optional Stop	M01	M01	M01	M01	M01
Subprogram Call	M98	M98	CALL or CYCLE DEF	CALL LBL	G65–G66 or Mazatrol page
Subprogram Return	M99	M99	M17 or RETURN	RET	RETURN

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🧠 Key Observations

• Fanuc & Haas use very similar G/M code sets (Fanuc compatibility).
• Siemens introduces named cycles (e.g., CYCLE81) instead of G81–G89.
• Heidenhain uses conversational programming with CYCL DEF syntax.
• Mazak (Mazatrol) often abstracts G/M codes behind menus or pages.

💡 For cross-platform programming, always confirm controller-specific behavior — even if the G-code is identical in name.

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📘 How to Use This Table

• For multi-brand shops: use it as a cheat sheet for transferring part programs.
• For post-processor development: ensure each CAM post aligns with correct syntax.
• For training and onboarding: teach new operators how same function differs across brands.

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✅ Final Tips

• Don’t assume G/M codes are universal.
• Use your machine’s parameter list or G-code guide (often stored in control).
• When in doubt, simulate first — especially with canned cycles or cutter compensation.
• In high-mix shops, label each program with the target controller:
  O1000 (HAAS VF-2SS) vs O1000 (SIEMENS 840D)

📌 Bookmark this guide as your universal CNC G/M code translator.

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▶️ Next Suggested Topic:

“Multi-Brand CNC Post Processor Design: How to Generate Compatible G-Code from One CAM Setup”

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