Free Online G-Code Viewer & Toolpath Simulator (3D Print & CNC)
Simulate 3D Printer & CNC Toolpaths Online. Simulate 3D printer and CNC toolpaths layer-by-layer with filament calculation, print time estimation, and extrusion inspection.
What is G-Code Visualizer and what does it do?
The G-Code 3D Toolpath Visualizer is an in-browser CNC and 3D printing simulator that renders slicing layers, calculates filament usage, and inspects toolpaths.
Simulate printer nozzle movements, review travel moves, verify layer heights, and estimate print durations before sending jobs to 3D printers.
- Simulate G-code toolpaths layer by layer with interactive slider.
- Display extrusion paths in emerald and rapid travel moves in dashed red.
- Calculate total filament length in meters and estimated print time.
- Inspect hotend and heated bed temperature commands (M104, M140).
How does G-Code Visualizer work?
Parses G0, G1, and Z layer commands, categorizes extrusion vs travel moves, maps millimeter coordinates to a virtual 220x220mm print bed, and renders toolpaths via HTML5 Canvas.
100% private: all processing happens locally in your browser using client-side WebAssembly, WebCrypto, WebAudio, and HTML5 Canvas. Your files are never uploaded to any server.
Who needs G-Code Visualizer?
3D Printing Enthusiasts & Makers
Inspect sliced G-code before heating printers to catch layer gaps or overhang issues.
CNC Machinists
Verify tool clearances and rapid travel paths to prevent machine collisions.
Supported file formats
G-Code 3D Toolpath Visualizer opens and processes the following file extensions directly in your browser:
.gcode.gc.nc.gcoHow to use G-Code Visualizer — step by step
- 1
Upload G-Code File
Drag and drop your sliced .gcode or .nc file.
- 2
Scrub Through Layers
Use the layer slider to simulate nozzle movement and infill.
- 3
Inspect Metrics
View filament length, estimated duration, and nozzle temperatures.
Frequently asked questions
Which 3D slicers are supported?
Compatible with G-code from Cura, PrusaSlicer, Bambu Studio, OrcaSlicer, and Simplify3D.
Does it show rapid travel moves?
Yes, toggle 'Travel Moves' to display non-extruding positioning travels.
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