Which format should you use?
| Format | Best for | Keeps units? | Keeps colour? |
|---|---|---|---|
| STL | Slicing and printing — universal support | No | No |
| 3MF | Modern printing, multi-material projects | Yes | Yes |
| OBJ | Blender, rendering, game engines | No | Via MTL |
| PLY | 3D scanning, photogrammetry, research | No | Per-vertex |
The short version: print it as STL if you want it to open anywhere, 3MF if you want the file to remember its units and colours, OBJ to move it into modelling software, and PLY if a scanner or research tool is involved.
Why in-browser conversion is better
Nearly every free converter online uploads your model, converts it server-side, and sends it back. That means a queue when the site is busy, a file size cap to control their costs, and a copy of your geometry on hardware you do not control.
Everything here happens inside your browser instead. That removes the queue, removes the size limit and removes the privacy question entirely — which matters when the part is a client's or under NDA.
What we deliberately do not convert
STEP / STP. STEP describes shapes with mathematical surfaces rather than triangles, so reading it needs a full CAD kernel, not a mesh parser. A shortcut implementation would produce subtly wrong geometry, and wrong geometry that looks plausible is worse than no tool at all.
G-code. Converting STL to G-code is not conversion, it is slicing — the output depends on your printer, nozzle, material, layer height and dozens of other settings. Use a real slicer. If you only want to know how long it will take, our print time estimator answers that from the STL directly.
Frequently asked questions
Which 3D file formats can I convert?
STL (binary and ASCII), OBJ, 3MF and PLY (ASCII and binary), in any direction — twelve conversion routes in total. STL is what slicers want, OBJ is what modelling software prefers, 3MF is the modern print format that keeps units and colour, and PLY is what most 3D scanners export.
Is my model uploaded to a server?
No. Files are parsed and written entirely inside your browser. There is no backend to send them to, which is also why there is no file size limit and no waiting in a queue. You can confirm it by watching the Network tab in devtools while you convert.
Is there a file size limit?
No. Since nothing is uploaded, the only real constraint is your own device memory. Large meshes convert fine on a normal laptop.
Can you convert STEP or STP files?
Not yet. STEP is a boundary-representation CAD format built from mathematical surfaces rather than triangles, so converting it requires a full CAD kernel rather than a mesh reader. We would rather ship nothing than ship a STEP converter that quietly produces wrong geometry.
Can you convert STL to G-code?
No, and nor can any converter — that is slicing, not converting. G-code is machine-specific toolpath instructions that depend on your printer, nozzle, material and layer height. Use PrusaSlicer, Orca, Bambu Studio or Cura for that. Our print time estimator will tell you how long the result should take.
Will converting fix a broken mesh?
No. Conversion faithfully carries the geometry across, including any holes or flipped faces. The converter tells you the triangle count, volume and whether the mesh is watertight when it loads, so you know what you are dealing with before printing.