OBJ to STL
Convert OBJ to STL for 3D printing: every face triangulated, binary or ASCII STL, with a watertight check before it goes to the slicer.
How it works
Open the OBJ
Drop the file: STL, OBJ, PLY, OFF, 3MF, GLB or glTF (with its .bin if it has one). It is read in your browser and shown in 3D.
Check it
Turn it with the mouse or a finger. The size, the triangle count and whether the mesh is closed are listed, so a bad file is caught before the printer or the game engine sees it.
Download the STL
Pick the format and download. Axes and units are converted for you: glTF is Y-up in metres, printers are Z-up in millimetres.
OBJ to STL converter: free and online
Convert OBJ to STL in your browser: drop in a OBJ file and download the STL. The file is converted on your own device and never uploaded, so this obj to stl converter is safe for private and confidential files.
OBJ is a common 3D model format read by Blender and most 3D software. STL is the 3D printing format: a closed surface of triangles that every slicer reads.
The paths come out at the real size you set, in millimetres or inches, ready for a laser, a CNC router, a vinyl cutter or a plotter.
More conversions from OBJ: OBJ to GLB, OBJ to glTF, OBJ to 3MF, OBJ to STEP.
Other conversions to STL: Sketch to STL, SVG to STL, Image to STL, Image to STL, GLB to STL, glTF to STL.
People also search for
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Why it matters
The right way up and the right size
A 20 mm part stays 20 mm and upright: glTF's metres and Y-up axis are converted to and from the millimetres and Z-up of STL, 3MF and slicers.
Checked against a reference
Every format pair is tested against trimesh: the same volume, surface area and size come back out.
Nothing uploaded
Client parts and unreleased designs stay on your computer. The model is read and written in this tab.
Questions
How do I convert OBJ to STL?
Drop your OBJ file on this page, check the preview, and press Download. The STL is made in a few seconds, with no sign-up.
Is my OBJ file uploaded anywhere?
No. The obj to stl conversion runs in your browser, on your own device. The file never leaves it.
Which 3D formats can I convert?
STL (binary and ASCII), OBJ, PLY (ASCII and binary), OFF, 3MF, GLB and glTF, in and out, in any combination.
Are colours and textures kept?
No: the shape is converted, every triangle of it, but not colours, textures or materials. The page says when the file had them. For printing and CAD that is what matters; for a textured game asset, keep the GLB.
Why is my glTF so small or lying on its side?
glTF measures in metres and stands models on the Y axis; STL and slicers use millimetres and the Z axis. This converter turns and scales between them, and "Keep axes and units as they are" turns that off.
Can it convert STEP or IGES?
Yes, into any of the mesh formats: drop the .step, .stp, .iges or .igs file and OpenCASCADE cuts its solids into triangles in your browser. The other way, a mesh is saved as a STEP solid made of flat faces (see the STL to STEP converter).
What about compressed glTF?
Draco and meshopt compressed glTF files are recognised and reported; export them again without mesh compression to convert them here.