G-code viewer
Drop a 3D file here
STL, 3MF, OBJ, PLY, GLB or G-code. The file opens in this browser tab and is not uploaded.
- File
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- Size (mm)
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- Volume
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- Triangles
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Measure it, cut a section, estimate the print
The free Extrude app does this on your phone, offline. Listed as “STL Viewer”.
What is a G-code file?
G-code is the list of moves a slicer writes for one printer. Each line tells the nozzle where to go and how much plastic to push. A G-code file only fits the printer and filament it was sliced for.
Slicers also write comments into the file: estimated time, filament length and weight, layer height and a preview image. Viewers read those to show a summary without printing.
How to use this viewer
- Drop the file on the dark area, or press Choose file.
- Drag to rotate, scroll or pinch to zoom, right-drag or two-finger drag to pan.
- Read the size, volume and line count under the view. Use Wireframe to see the mesh.
Opening G-code files on a phone
On a phone, the app shows the summary rather than the 3D toolpath: time, filament, layers, printer model and the thumbnail. That is usually what you need before sending a job.
Questions
Can I check a G-code file before printing?
Yes. Drop it here to see the toolpath and the print size, or open it in the Extrude app to read the time, filament and layer count the slicer wrote.
Why are travel moves not shown?
The viewer draws extrusion moves, the lines that become plastic, so the part is easy to see.
Can I turn G-code back into STL?
Not reliably. G-code is a list of nozzle moves, not a surface. Keep the original STL or 3MF.
Is the file uploaded?
No. Large G-code files can take a few seconds because your own device does the work.
Other viewers
Every page opens every format. These cover what is different about each one.