gCode Analyzer

gCodeViewer is an online GCode visualizer and analyzer that works in most modern browsers on any operating system. Simply drag your *.gcode file into the interface, and you can visualize your GCode layer by layer in 2D, analyze print speeds, retracts, and overhangs, and even animate the sequence of layer printing. It also provides print time estimates, material usage, and more.

The tool is multiplatform, works offline, and doesn’t upload or download any files except for the application itself. It can also parse nozzle and filament diameters from GCode, though manual input may be required in some cases. gCodeViewer is open-source, so you can use and modify it as needed.