Convert STL to OBJ in your browser
Drop an STL file below and get an OBJ back. The conversion happens entirely inside this browser tab using your own machine, so your file never leaves your computer and is never sent to a server.
STL and OBJ both store the same thing here: a mesh made of triangles. This tool rewrites that mesh from one format into the other, exactly as-is, with nothing added and nothing dropped.
How it works
Good to know
FAQ
Will my model look the same after converting to OBJ?
Yes. STL and OBJ are both triangle meshes, and this tool copies every vertex and face over unchanged. The geometry, down to each triangle, is identical. What you will not get is color or surface texture, because an STL never stored any to carry over.
Why doesn't the OBJ have any color or material?
STL files only describe shape, not appearance. There is no color, material, or texture data inside an STL, so there is nothing for the OBJ to inherit. If you need a colored or textured OBJ, you have to add materials yourself afterward in a 3D editor; no converter can recover data that was never in the source file.
Are the units and scale preserved?
The numbers are copied over exactly, so a model that measured 50 by 20 in STL stays 50 by 20 in OBJ. The catch is that neither STL nor OBJ records what those numbers mean (mm, cm, inches), so the unit is assumed by whatever program opens the file. If your slicer or CAD tool treats OBJ as a different default unit than your STL, the part can appear scaled. Check the import units when you load the OBJ.
Is there a file size limit?
There is no fixed cap we impose, but because everything runs in your browser tab, very large meshes (hundreds of MB, millions of triangles) are limited by your device's memory. Most printable and CAD-exported parts convert in a second or two. If a huge file stalls, try closing other tabs to free up memory.
Will the OBJ still print correctly?
For 3D printing, OBJ and STL carry the same geometry, so a slicer will treat them the same way once units match. OBJ is slightly more verbose on disk, but the printed result is identical. Many slicers actually prefer STL for printing, so only convert to OBJ if your target tool specifically needs it.
Is my file really not uploaded anywhere?
Correct. The conversion code runs in your browser using JavaScript, and your file is read directly from your disk into the tab's memory. Nothing is transmitted to us or to any server. You can confirm this by opening your browser's network tab and watching that no upload request fires when you convert.