Are my OBJ files uploaded anywhere?

No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and watch that nothing is sent while the file converts.

Is converting OBJ to STL free?

Yes, without a limit on how many files you convert and with no watermark on the result. Files up to 100 MB are covered by the free plan.

Does converting OBJ to STL lose quality?

OBJ and STL describe content in fundamentally different ways, so the conversion is a reconstruction rather than a copy. The result is faithful, but not byte-for-byte equivalent. Geometry only. Materials, colours, textures and animation are not carried across, and a model placed several times comes back with each copy baked into its own position.

Do I need to install anything to open STL files?

No installation is needed for the conversion itself — it runs in the browser you already have. Opening the STL afterwards needs whatever software normally handles Stereolithography on your device.

OBJtoSTL

Convert OBJ to STL

Up to 3 files at once, 100 with Pro. Mixed formats are fine.

You can convert OBJ to STL free and without an account: drop the file above and the STL is ready to download in a second or two. The conversion happens inside your own browser, so the file is never uploaded — it works on Windows, Mac, Linux, iPhone and Android, and keeps working with the network switched off.

What OBJ and STL are for

A plain-text 3D mesh format every modelling program can read.

The 3D printing standard. Triangles only — no colour, no material, no texture.

How to convert OBJ to STL

Drop your OBJ file onto this page, or click to pick one.
Choose STL as the target. The conversion runs inside your browser — the file is never uploaded.
Download the finished STL file.

OBJ vs STL: what changes

OBJ compared with STL
	OBJ	STL
Full name	Wavefront Object	Stereolithography
File extension	.obj	.stl
Media type	model/obj	model/stl

Quality: The result is a close reconstruction rather than an exact copy. Check it before relying on it.
Where it runs: This conversion runs inside your browser. Your file is never uploaded, and it works with the network disconnected.
What can be lost: Geometry only. Materials, colours, textures and animation are not carried across, and a model placed several times comes back with each copy baked into its own position.

OBJ to STL: common questions

Are my OBJ files uploaded anywhere?: No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and watch that nothing is sent while the file converts.
Is converting OBJ to STL free?: Yes, without a limit on how many files you convert and with no watermark on the result. Files up to 100 MB are covered by the free plan.
Does converting OBJ to STL lose quality?: OBJ and STL describe content in fundamentally different ways, so the conversion is a reconstruction rather than a copy. The result is faithful, but not byte-for-byte equivalent. Geometry only. Materials, colours, textures and animation are not carried across, and a model placed several times comes back with each copy baked into its own position.
Do I need to install anything to open STL files?: No installation is needed for the conversion itself — it runs in the browser you already have. Opening the STL afterwards needs whatever software normally handles Stereolithography on your device.