Convert OBJ to STL free in your browser. Set the real size, find and repair holes, then export a print-ready STL or 3MF for your slicer.
Drag your .obj file into OwlCAD in your browser, check its size, then click Export and save it as STL. There is nothing to install.
An OBJ made for rendering is often not ready to print. Find out before the slicer does.
OBJ files carry no units. The import makes a best guess at the size, and one click rereads the file as millimetres, centimetres, inches or metres.
The import says whether the mesh is watertight, and offers a repair that closes holes and turns inside-out faces the right way.
Run Print check for thin walls and overhangs before you export STL or 3MF.
Drop the file on the build plate, set its size, and export an STL for your slicer.
It opens on your device, it is saved to your workspace as you work, and it exports back out in the format your slicer wants.
Your browser reads and renders the model itself, so it appears as soon as you drop it in — you are never queued behind anyone else’s upload, and the file does not travel anywhere before you can see it.
Most online viewers forget your file the moment you close the tab. OwlCAD keeps the model in your own workspace and syncs it as you work, so it is still there when you come back to this browser. Create a free account and it follows you to any device, and your projects dashboard lets you delete anything you no longer want.
When you are done, export STL, 3MF, OBJ, GLB or STEP — the format your slicer or your colleague actually needs, not a project file that only opens here.
OBJ has no units, so a model made in centimetres or metres can arrive a tenth or a thousandth of its real size. The import message offers to read the file as millimetres, centimetres, inches or metres: pick the unit it was made in.
They are not carried over. STL stores geometry only, so no OBJ to STL conversion keeps them. If you want colour on the print, colour the parts in OwlCAD and export 3MF instead.
The import tells you and offers a repair. Export works either way and writes the triangles you see, but a slicer can struggle with holes, so repair first when you can.
Yes. Importing, editing and exporting in OwlCAD is free, and you can start without an account. AI generation is the optional Pro upgrade.