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STLOBJ

STL to OBJ converter

Turn STL files into OBJ for Blender, game engines and 3D apps, in millimetres or upright in metres.

  • Nothing uploaded
  • No sign-up
  • Free, no limits

Drop your STL file here

or paste it, or pick it from your device

.stl

  1. Drop your STL file
  2. Check it in 3D
  3. Download OBJ

Good to know

How to convert STL to OBJ

  1. Drop one or more STL files above. They're read on your device, not uploaded.
  2. Choose who the OBJ is for: Slicer or CAD keeps millimetres with Z up, like the STL. Blender writes metres with Y up, so the model opens upright and at its real size with Blender's default import settings.
  3. Download the OBJ. Several STLs become separate, named objects in one OBJ file.

STL or OBJ?

Both store a mesh of triangles. STL is the 3D printing standard and has nothing else: no units, no colours, no object names. OBJ is a plain-text format almost every 3D program reads, and it can hold several named objects and materials. Convert to OBJ when a 3D app, a game engine or a renderer wants it; for printing, STL or 3MF is simpler.

Sizes and orientation

  • STL files don't store a unit. Nearly all are in millimetres, which is what the Slicer or CAD option keeps. If yours looks tiny or huge, fix it first in Resize STL.
  • 3D printing files are Z up. Blender, Unity and most game engines expect Y up, which the Blender option handles. Unity also reads one unit as one metre.

Going the other way? Use OBJ to STL.

Questions

How do I convert STL to OBJ for free?

Drop the STL into the tool on this page and click Download OBJ. It's free, needs no sign-up, and the file never leaves your device.

Will the OBJ open the right way up in Blender?

Pick Blender under "The OBJ is for" before downloading. The OBJ is then written Y up in metres, which Blender's default import turns into an upright model at its real size.

Can I convert several STLs into one OBJ?

Yes. Drop them together (or add more after the first): each becomes a named object in the same OBJ.

Does OBJ keep colours from an STL?

STL has no colours to keep. Colour the objects in your 3D app, or for multi-colour printing put the parts in a 3MF with STL to 3MF.