Free STL File Converter

STL is the format every slicer reads, and the one format that carries no colour, no units and no shared vertices. Converting in either direction is routine, but what you gain and lose is not symmetric — this page handles both.

Drop a file to convert it STL, OBJ, GLB, glTF, PLY, 3MF, DAE, OFF — the format is detected from the file itself. Max 50MB

Output format

Convert to

Is your STL ready to convert?

Is the mesh watertight? An open shell will slice into nonsense.
Any non-manifold edges? Thin walls and T-junctions confuse slicers.
Are the normals pointing outward? Flipped normals invert the solid.
Are the units sane? STL carries none, so 3 units could be 3 mm or 3 m.
Is the file size reasonable? A 200 MB STL slows every downstream step.

STL Editor All Converters

Turn other formats into STL

3MF → STL 3MF colour model to plain STL Blend → STL Blend to STL DWG → STL DWG to STL FBX → STL FBX to STL GLB → STL glTF Binary to STL for slicing glTF → STL glTF to STL IGES → STL IGES to STL IGES → STL IGES to STL PNG → STL Turn a PNG or JPG into a printable relief OBJ → STL Wavefront OBJ to 3D-printable STL PLY → STL Convert 3D scan PLY files to STL SLDPRT → STL SLDPRT to STL STEP → STL STEP to STL SVG → STL Extrude SVG vector logos into printable 3D models Parasolid → STL Parasolid to STL

Turn STL into other formats

STL → 3MF STL to 3MF STL → GLB STL to GLB STL → glTF STL to glTF STL → OBJ Turn an STL print file into an editable mesh STL → USDZ STL to USDZ

STL vs OBJ vs 3MF vs GLB

Format	Colour	Units	Editable mesh	Best for
STL	No	No	No	Slicing and printing
OBJ	Via .mtl	No	Yes	Editing in a modelling app
3MF	Yes	Yes	Yes	Printing with colour
GLB	Yes	Yes	Yes	Web, AR and game engines

How to convert a file

Drop your file

STL, STEP, OBJ, FBX, GLB, glTF, PLY, 3MF, DAE or OFF. The format is read from the file itself, so a mislabelled extension is not a problem.

Pick the output format

Choose STL for printing, or OBJ, GLB, PLY or 3MF when you need an editable or web-ready result.

Preview, convert, download

Check orientation and scale in the viewport first — conversion will not fix a model that was authored at the wrong size.

Converter questions

How do I convert a file to STL?

Drop it into the uploader above. The format is detected automatically, then choose STL as the output. The result is a binary STL ready for any slicer.

How do I convert an STL to OBJ or GLB?

Same uploader, different output. Converting STL to OBJ welds the duplicated vertices back into an indexed mesh, which is what makes it editable again.

Can I convert STL to STEP or other CAD formats?

No, and no online tool honestly can. STL is a triangle mesh; STEP is exact boundary-representation geometry. Going back to real CAD surfaces requires re-modelling, not conversion.

Will the conversion fix a broken mesh?

It will not. Use the STL editor to fill holes, merge duplicate vertices and fix normals first, then convert.

Why is my STL larger than the file I started with?

STL stores three vertices per triangle with no index buffer, so a dense indexed mesh can grow several times over. Exporting binary rather than ASCII keeps it as small as possible.

What is the maximum file size?

50 MB per conversion. For anything larger, decimate first — a slicer will not thank you for a 200 MB mesh.

Does the converter keep colours?

Into STL, no — the format cannot store them. Converting out of STL, there is no colour to recover. Use 3MF when colour has to survive.

Is my file uploaded?

For conversion, yes: the mesh pipeline runs on the server so it can handle formats the browser cannot parse. The preview itself is rendered locally.