See where the printer will move
View outer walls, inner walls, infill, supports, and moves that do not print plastic.
PRIVATE G-CODE VIEWER / 01
Free Online
G-code Viewer
See the toolpath before you print. Open 3D-printer G-code in 3D, inspect one layer in 2D, and read the original commands—all in your browser. No upload or account required.
- FILES.GCODE / .GCO / .G
- VIEWS3D / 2D / G-CODE
- ACCESSFREE / NO ACCOUNT
01
INTERACTIVE VIEWER
See the full toolpath
in 3D.
Try the live demo below. Rotate the model, zoom in, view one layer from above, or show travel moves before opening your own file.
Reading this fileThe file is being read locally in this browser.
Drag to rotateHold Alt/Option + scroll to zoom
Reading locally
LAYER001
WHY USE A G-CODE VIEWER?
A final look
before printing.
Check before printing
Compare dimensions, inspect each layer, and look for gaps or unexpected travel moves before spending time and filament.
Read key details at a glance
See estimated print time, filament use, layer height, requested speed, and print size from the G-code.
FIELD GUIDES / 05
Inspect the file, not just the model.
Five focused workflows for the questions that come up after slicing. Each guide tells you what to inspect, which view to use, and where the file stops being evidence.
01 / Pre-print check
How to inspect G-code before printing
A final G-code check can catch the wrong export, an unexpected footprint, missing layers, odd feature paths, or long travel moves before they consume machine time and filament.
Read guide ↗02 / File workflowHow to open a G-code file
G-code is plain-text machine instruction, but opening it in a text editor does not show the shape of the toolpath. A viewer turns supported motion commands into a spatial preview while keeping the source available.
Read guide ↗03 / File estimatesRead print time, filament, and dimensions from G-code
A G-code file can contain slicer estimates and enough motion to calculate useful measurements. The important part is knowing which values were declared, measured, estimated, or assumed.
Read guide ↗04 / Travel diagnosisFind travel moves that may contribute to stringing
Stringing happens on the physical print, but the file can reveal where the nozzle travels without extrusion and whether retraction commands or extrusion-only retract moves appear around those journeys.
Read guide ↗05 / Surface inspectionHow to locate a likely Z seam in G-code
A perimeter loop has to start and end somewhere. When those points align across layers, the printed surface may show a vertical seam—but the viewer displays paths, not the final surface artifact.
Read guide ↗PRIVATE BY DEFAULT
Your design stays
on your machine.
The viewer reads your file with the browser’s local File API. Toolpaths are rendered on your device and are never sent to our server.
- 01No account required
- 02No G-code upload
- 03No software installation
SUPPORTED INPUT
Made for sliced
3D prints.
CURAPRUSASLICERBAMBU STUDIOORCASLICERSUPERSLICER
Open common text G-code files produced for 3D printers.
Reads straight moves, arcs, extrusion, coordinates, offsets and common slicer comments.
This viewer is for 3D-printer G-code. CNC files and full machine simulation are not supported.
FIELD NOTES / FAQ
What to know
before you load.
Is the viewer really free?+
Yes. The viewer is free to use and does not require an account.
Does my file leave the browser?+
No. File reading, analysis, and toolpath rendering happen locally in your browser. The G-code is not uploaded.
How accurate is the print time estimate?+
When the slicer stores a time estimate in the file, the viewer uses it. Otherwise it calculates a motion-based estimate. Printer acceleration, heating, and firmware behavior can change the real result.
Can it replace my slicer preview?+
It is an independent final check, not a slicer or machine simulator. Always review critical jobs in your slicer and follow your printer manufacturer’s safety guidance.
READY WHEN YOUR FILE IS