Free STL to OBJ 3D Model Converter, No Sign-up and No Upload
This free STL to OBJ converter turns 3D-printing meshes into Wavefront OBJ files. There is no sign-up or login, no watermark, and no upload: your model is converted in your browser and never leaves your device.
STL is the standard input for 3D printing, while OBJ is supported by almost every 3D tool. Convert when you want to open a printable model in modelling or rendering software.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
How to convert
- Drag your STL files onto the page or choose them with the file picker.
- Pick OBJ as the target format.
- Check the options, then start the conversion.
- Download each OBJ file, or take a batch as one ZIP.
Features
- Runs natively in your browser with no engine download.
- Outputs a plain-text Wavefront OBJ mesh.
- Works with the geometry stored in the STL.
- Batch conversion of several models.
- No watermark and no account.
Supported formats
| Format | Read | Write | Notes |
|---|---|---|---|
| STL (3D).stl | Yes | Yes | The standard input for 3D printing: geometry only, as triangles. |
| Wavefront OBJ.obj | Yes | Yes | Plain-text 3D mesh format from Wavefront, supported by almost every 3D tool. |
About the formats
STL versus OBJ
STL stores geometry only, as triangles, with no colour, texture or material data. OBJ is a plain-text mesh format from Wavefront that tools read widely, with materials kept in a separate .mtl file. Converting STL to OBJ cannot add colour or texture that the STL never had.
The shape itself carries over, so the result is a geometry-only OBJ you can enrich in your 3D software.
Privacy: how it works
- Your 3D models stay on your device. The page reads each file with the browser's file API, converts it with code running in the tab, and hands the result back as a download. No upload happens, so there is no copy of your file on our servers to protect, delete or leak.
- There is nothing to sign up for and no login. The converter does not ask for an email address, and it does not need to know who you are to do its job.
- You can check the claim yourself: open your browser developer tools, watch the Network tab while a file converts, and you will see no request that carries your file.
- Designs and prototypes can be valuable. The mesh is read and rewritten locally, so your model is never copied to anyone else.
Tips
- Expect an untextured, single-material model, because STL has no appearance data.
- Open the OBJ in your modelling tool and add materials there.
- Check the scale and units after import, since STL does not record them.
- Keep the original STL for printing.
- Convert several parts at once if they belong to the same project.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial, no credit card and no watermark added to your results. Ulkaa Tool does the conversion with your own device, so there is no server bill to pass on to you.
Are my files uploaded?
No. Your 3D models are read and converted inside your browser and are never sent to Ulkaa or to anyone else. The result is created on your device and you save it from there.
Do I need an account?
No. There is no sign-up and no login. Open the page, add your files and convert. An Ulkaa account is not needed for anything on this tool.
Is there a file size limit?
No limit is set by us. The real limit is your device: the conversion uses your own memory and processor, so very large files can be slow, and a very big batch may need to be split into smaller runs.