G-code Viewer Online
Drop a 3D printer or CNC G-code file to see its toolpath layer by layer, colored by feature, speed or layer, with the print time, filament and size, and click any move to see its line. No account and no upload.
GCode Viewer, CNC Viewer & 3D Print Preview for VS Code and Cursor, free
- Click a .gcode file in VS Code to see the toolpath in 3D: orbit, pan and zoom, Top and Front views, and a layer slider.
- Play the print with a nozzle marker at 1x to 5000x, and Go to line opens the text at the first line of a layer.
- CNC mode for .nc, .ngc and .tap programs with rapids, cuts, helical arcs, plunges, tools and the cycle time.
Optional Zovo Pro, USD 19 once: a job report per layer, compare two G-code files, and a folder summary. 3 free tries for each.
Drop a .gcode or .nc file here
or
G-code from PrusaSlicer, Cura, OrcaSlicer, Bambu Studio, SuperSlicer and Simplify3D, and CNC programs (.nc, .ngc, .tap, .cnc), up to 500 MB.
Scroll to zoom, drag to move, click a move to see its line of G-code. Keys: Up and Down step layers, Home and End, S one layer, T travel.
Open this in VS Code or Cursor
The free GCode Viewer extension opens a .gcode file with a click inside VS Code and Cursor as a 3D toolpath you can orbit, plays the print with a nozzle marker at up to 5000x, and opens the text at the line of any move. A 59 MB file with 1.5 million moves draws in about 2 seconds.
Free, MIT license. About GCode Viewer for VS Code.
Zovo Pro
Job reports, compare two G-code files and folder summaries. Zovo Pro, USD 19 once.
In the GCode Viewer extension, Zovo Pro gives a job report with the time and filament of every layer (CSV, Markdown or JSON), compares two slices or CAM outputs side by side, and writes one CSV row per G-code file in a folder with time, filament, layers and slicer. Each Pro tool works 3 times for free. One payment covers the Pro tools in 22 Zovo extensions. Everything that is free stays free.
After a card payment you get a key on the page. With GitHub Sponsors you sign in from the extension. Details on the Zovo Pro page.
Related tools
- STL Viewer, OBJ, GLB & glTF Preview. Opens 3D models in VS Code before you slice them.
- DXF Viewer. Opens DXF drawings from CAD programs in VS Code.
- Hex Viewer. Opens any binary file as hex in VS Code.
- STL Viewer Online, free in your browser.
- DXF Viewer Online, free in your browser.
- VCD Viewer Online, free in your browser.
Questions
Is my G-code uploaded anywhere?
No. The page reads the file inside this tab. Its Content Security Policy sets connect-src to none, so the page cannot send your file anywhere, and it loads no library. Open the Network tab of your browser tools and you will see no request when a file opens.
What does it show?
A top or front view of the toolpath with a layer slider. Layers below the current one are shown dimmed, or pick One layer. Colors follow the slicer's feature comments (outer wall, inner wall, infill, skin, skirt, support), the speed, the layer or the tool. Click a move and the page shows its line number and the line itself.
How is the print time worked out?
From the feed rate and length of every move, plus G4 dwells. Acceleration is not modelled, so a real print usually takes a little longer. When the slicer wrote its own estimate (Cura TIME, PrusaSlicer, OrcaSlicer or Bambu Studio), the page shows it next to its own.
How is the filament weight worked out?
From the E axis, absolute or relative, with G92 E0 resets, for the filament diameter and density in the boxes under the stats. PLA is 1.24 g/cm³, PETG 1.27 and ABS 1.04.
Does it read CNC programs?
Yes. A file with no extrusion opens in CNC mode: G0 rapids, G1 cuts, G2 and G3 arcs with I and J or R, plunges, inches (G20), relative moves (G91), G92 and G28. The slider steps through Z passes, and the stats give the cycle time, cut and rapid lengths, tools and spindle speed.
How big a file can it open?
Up to 500 MB. The moves are kept in compact arrays and drawn one color at a time, so a file with a million moves still opens in a few seconds. The VS Code extension reads big files in a worker in 4 MB chunks.
What is free and what is Zovo Pro?
Everything on this page is free. In the GCode Viewer extension the 3D view, playback, Go to line, stats and CNC mode are free too. A job report per layer, comparing two G-code files and a folder summary are Zovo Pro, with 3 free tries each. One USD 19 payment covers the Pro tools in every Zovo extension.