Convert STL files to OBJ free in your browser — no signup, no install, and the file is never uploaded to a server. OBJ keeps full quality with no further loss.
Add your STL file
Drag the STL file onto the drop area above, or click it to pick a file from your device. You can add several files at once.
Confirm OBJ as the output
OBJ is already selected as the output format on this page. This format converts straight through with no extra settings.
Run the conversion
Press the convert button. Processing happens on your own device, so the time depends on your computer rather than a server queue.
Download the OBJ file
When it finishes, download the OBJ file. Converting multiple files gives you the option to download them together as a ZIP.
The de facto standard for 3D printing, describing surfaces purely as a mesh of triangles. It cannot carry color or material information.
A text-based 3D model format read by nearly all 3D software. Materials are described alongside it in a separate MTL file.
Yes. STL to OBJ conversion is completely free with no signup, no watermark, and no daily limit on the free plan for ordinary use.
No. The conversion runs entirely inside your browser using WebAssembly, so the STL file never leaves your device. That is also why it works without an internet connection once the page has loaded.
It can go either way. Both formats are lossless, so nothing is thrown away — the size difference comes from how each one packs the same data.
The free plan handles files up to 200MB. Because processing happens on your own device, very large files depend on your computer's memory rather than a server quota.
3D & CAD converter
What each file format is, what it is used for, and which formats it can be converted to.
Open converter Browse the full format reference