{"id":15900,"date":"2020-12-09T09:00:00","date_gmt":"2020-12-09T17:00:00","guid":{"rendered":"https:\/\/www.autodesk.com\/products\/fusion-360\/blog\/?p=15900"},"modified":"2025-08-08T07:28:46","modified_gmt":"2025-08-08T14:28:46","slug":"getting-started-with-g-code","status":"publish","type":"post","link":"https:\/\/www.autodesk.com\/products\/fusion-360\/blog\/getting-started-with-g-code\/","title":{"rendered":"G Code List: G and M Codes Explained for CNC Programming"},"content":{"rendered":"\n

Learn the essentials of G-code, review a handy G code list, and see how the most common G and M codes for CNC machining shape every program.<\/em><\/p>\n\n\n\n

\"CNC<\/figure>\n\n\n\n

In this article, we\u2019ll be talking about the core component of every CNC program \u2013 G-code, and we\u2019ll walk through a practical G Code list you can use for easy reference.<\/p>\n\n\n\n

G & M-codes will make up the bulk of your CNC program, so keeping a concise G and M code list nearby speeds up troubleshooting and edits.<\/p>\n\n\n\n

Even if you never end up writing your own CNC program by hand, understanding G-code\u2019s fundamentals will give you a leg up in your CNC programming career, especially once you memorize the most common entries in the G code list.<\/p>\n\n\n\n

Some guides recommend memorizing the most common G and M codes, but building your own G & M code list within Fusion\u2019s notes can be even more effective.<\/p>\n\n\n

What is G-code?<\/h2>\n\n\n

Programming is a fundamental skill for all types of CNC machining<\/a>, even as automation and new technology seem to be replacing programming tasks. Every machinist still needs to understand how their programs and tools work. Whether you\u2019re new to CNC programming<\/a> and its most common language, G-code<\/a>, or you\u2019ve been writing code by scratch for years, CNC programming codes can still feel like a foreign language. And to make things worse, every machine speaks a different dialect you have to understand. Do you understand what they\u2019re saying? Here are the G-code programming basics and g-code language you need to know to efficiently understand and write programs that produce high-quality products.<\/p>\n\n\n

What is G-code language?<\/h3>\n\n\n

G-code<\/a> is a programming language for CNC that instructs machines where and how to move. Most machines speak a different \u201cdialect\u201d of G-code, so the codes vary depending on type, make, and model. Each machine comes with an instruction manual that shows that particular machine\u2019s code for a specific function.<\/p>\n\n\n\n

G-code stands for \u201cgeometric code,\u201d and follows some variation of the alpha numeric pattern:<\/p>\n\n\n\n

N## G## X## Y## Z## F## S## T## M##<\/p>\n\n\n\n

N: Line number
G: Motion
X: Horizontal position
Y: Vertical position
Z: Depth
F: Feed rate
S: Spindle speed
T: Tool selection
M: Miscellaneous functions
I and J: Incremental center of an arc
R: Radius of an arc<\/p>\n\n\n\n

Alpha numeric codes are used for G-code programming as they are a simple way to:<\/p>\n\n\n\n

    \n
  1. Define motion and function (G##)<\/li>\n\n\n\n
  2. Declare a position (X## Y## Z##)<\/li>\n\n\n\n
  3. Set a value (F## and\/or S##)<\/li>\n\n\n\n
  4. Select an item (T##)<\/li>\n\n\n\n
  5. Switch something on and off (M##), such as coolant, spindles, indexing motion, axes locks, etc.<\/li>\n<\/ol>\n\n\n\n

    For example,<\/p>\n\n\n\n

    G01 X1 Y1 F20 T01 M03 S500<\/p>\n\n\n\n

    would generally indicate a linear feed move (G01) to the given XY position at feed rate of 20. It is using Tool 1, and the spindle speed is 500. Miscellaneous functions will vary from machine to machine, so in order to know what the m-code means, the machine\u2019s instruction manual will need to be referenced.<\/p>\n\n\n

    CNC programming codes: machine motion<\/h3>\n\n\n

    Everything a machine can do is based on three basic types of motion:<\/p>\n\n\n\n

      \n
    1. Rapid move: a linear move to an XYZ position as fast as possible<\/li>\n\n\n\n
    2. Feed move: a linear move to an XYZ position at a defined feed rate<\/li>\n\n\n\n
    3. Circular move: a circular move at a defined feed rate<\/li>\n<\/ol>\n\n\n\n

      Every G-code tells the machine which variation of these basic motions to perform, and how to perform it.<\/p>\n\n\n\n

      X and Y are Cartesian coordinates<\/a> for horizontal and vertical position, and Z represents the depth of the machine. These alpha numerals will follow the motion\/function command (G) to declare the position of the machine.<\/p>\n\n\n\n

      Next, F determines the feed rate (for feed moves or circular moves), while S determines the spindle speed. T is used to select a tool. Other alpha numerals used in programming might include I, J, and R, which have to do with arc centers and radii.<\/p>\n\n\n

      Miscellaneous CNC machine codes<\/h3>\n\n\n

      The line of a program might also include m-codes, which are generally CNC machine codes that tell a machine how to perform an action. While not guaranteed to be the same across machines, some common, standard m-codes are:<\/p>\n\n\n\n