G-Code – The Complete Guide to CNC Programming

G-Code is the universal programming language of CNC machines. It is the set of instructions that tells a CNC machine how to move, where to cut, at what speed to feed, and how to execute operations with precision. Without G-Code, CNC machines such as milling centers, lathes, and machining centers would not be able to perform automated manufacturing tasks.

Every hole drilled, every slot milled, and every contour shaped is guided by G-Code commands. It is the bridge between CAD/CAM design software and the physical CNC machine, making it one of the most important elements of modern precision manufacturing.

How Does G-Code Work?

G-Code uses lines of text (program blocks) that contain commands for the machine to follow. Each command typically starts with a letter (such as G or M) followed by numbers that define movement, speed, or auxiliary functions.

Example: