How to Open STL Files in PrusaSlicer
PrusaSlicer is Prusa Research's free slicer for Prusa printers and many others.
Short answer · Built in
Yes. PrusaSlicer opens STL files as shipped: File › Import › Import STL/3MF/STEP/OBJ/AMF… (Ctrl+I).
Import STL into PrusaSlicer, step by step
- 1Check the fileFind out what units the part was designed in. Almost every printable STL is in millimetres, but the file itself doesn't say.
- 2Import into PrusaSlicerFile › Import › Import STL/3MF/STEP/OBJ/AMF… (Ctrl+I).
- 3Check scale and orientationPrusaSlicer works in millimetres and is Z-up. STL files are unitless (slicers assume millimetres), so the size depends on what the exporter assumed.
- 4Place it and sliceLay the flattest face on the plate, confirm the dimensions in the object panel, and slice. Slicers ignore textures and animation.
What comes through
| Shape | Yes, always. |
| Colours and materials | Ignored: PrusaSlicer only uses the shape. |
| Textures | Not used by a slicer. |
| Animation | PrusaSlicer doesn't play animation. |
Things to watch for
- STL is read in millimetres.
- Press F to lay a model flat on a selected face, and use the Cut tool (C) to split tall models.
Questions
- Does PrusaSlicer support STL files?
- Yes. PrusaSlicer opens STL files as shipped: File › Import › Import STL/3MF/STEP/OBJ/AMF… (Ctrl+I).
- Why is my STL model the wrong size in PrusaSlicer?
- STL files are unitless (slicers assume millimetres), while PrusaSlicer works in millimetres. PrusaSlicer asks to scale tiny models up from inches; check the size panel either way.
- What is the best 3D format for PrusaSlicer?
- 3MF and STL are the most reliable choice for PrusaSlicer. STL is one of them, so you're already using a good option.
Menu names follow Prusa Research's current release. Check the official PrusaSlicer documentation if your version differs.
Written with AI assistance by the Renderlyst team in October 2026. Format support reflects each app's current release as we understand it, and we link the official documentation so you can confirm it for your version. Spotted something out of date? Email alishbakhalid766@gmail.com.