Free OBJ to STL converter
Ready for your slicer

Drop an OBJ file from Blender, a 3D scan, Sketchfab or a game and save it as STL for 3D printing. The size and a watertight check show before you download.

The conversion runs in your browser, so the model never leaves your computer.

Free, no sign-up. Your file stays on your computer. It is opened and converted in this browser tab and is never uploaded to us or anyone else.

File will not convert, or the model needs cleaning up? Our team fixes and converts it for you. Send us the file and we reply with a fixed price. Send the file

  • OBJ to binary or ASCII STL
  • Size and a watertight check before download
  • Or save as 3MF to keep the colours
How it works

How to convert OBJ to STL

3 steps, and the file never leaves your computer.

1. Drop the OBJ file

Drop the .obj file. If it comes with an .mtl file and textures, you can leave them out: an STL has no colours.

2. Check the size and the mesh

The model opens in 3D with its size and triangle count, and whether it is a closed solid, which is what a slicer needs.

3. Download the STL

Binary STL is the smallest and what slicers expect. Choose ASCII only if another program asks for it.

Good to know

What changes when OBJ becomes STL

Colours, units, open meshes and several objects.

Colours and textures are dropped

STL stores only the shape. To keep the colours for a multi-colour printer, save as 3MF instead, which this converter also writes.

OBJ has no units

An OBJ file does not say if it is in millimetres or metres. Check the size shown before you download, and scale the model in your slicer if it is 10 or 1000 times off.

Scans and game models are often open

A model made for screens can have holes or loose faces. The watertight check tells you before you print. Close the holes in Blender or Meshmixer if it says no.

Several objects become one STL

Every object in the OBJ ends up in one STL file, in its place. Split them in your slicer if you want to print them apart.

From 3D file to images

What we make from 3D files

Product companies, game studios and architects send us their models to be turned into images and films that sell.

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3D product rendering

Photoreal studio and lifestyle images of your product, made from the model.

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3D modeling

Clean models from drawings, photos or a rough mesh, and broken files repaired.

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Architectural visualization

Photoreal images of buildings and interiors from your model or drawings.

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OBJ to STL FAQ

Questions about OBJ to STL

Formats, quality and privacy.

Ask us a question
How do I convert OBJ to STL for free?
Drop the OBJ file on the converter on this page, check the size and the watertight result, and click Convert and download. It is free, with no sign-up and no watermark.
Will the STL keep the colours of my OBJ?
No. STL has no colours or textures. If you print in several colours, save as 3MF here instead: it keeps the colours and every slicer reads it.
Why is my STL the wrong size in the slicer?
OBJ files carry no units, so a model made in metres can look tiny in a slicer that expects millimetres. Scale it by 1000 in the slicer, or by 0.1 if it was made in centimetres.
Can I convert STL back to OBJ?
Yes, with the STL to OBJ converter. The OBJ will have the same shape and no colours, because the STL had none.
Is my file uploaded?
No. The model is opened and converted in this browser tab on your own computer and is never sent to us or anyone else.
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