Mirror STL File Online
Open an STL, pick X, Y or Z and download the mirrored copy. The triangles are re-wound so the normals still point outward, so your slicer sees a clean solid. Nothing is uploaded.
How to mirror an STL file
- 1
Open the file
Drop an STL, 3MF, OBJ, PLY or GLB file (up to 100 MB) on the box, or try the sample letter F.
- 2
Pick the axis
Mirror X swaps left and right, Mirror Y swaps front and back, Mirror Z swaps top and bottom. You can combine them.
- 3
Check the preview
The original (grey) and the mirrored copy (green) sit side by side. Drag to turn the view.
- 4
Download
Press Download mirrored STL and open it in your slicer. Size and position on the bed stay the same.
What the STL mirror tool does
The details that matter for printing.
| Input formats | STL (binary or ASCII), 3MF, OBJ, PLY and GLB, up to 100 MB. A 3MF with several parts is mirrored as one assembly, so the parts keep their places. |
|---|---|
| Mirror axes | X, Y and Z, alone or together. The mirror plane goes through the middle of the model. |
| Normals | Mirroring turns every triangle inside out. The tool swaps two corners of each triangle afterwards, so the normals point outward again and the mesh is still a printable solid. |
| Size and placement | The size does not change. The model stays centred where it was and stays on the bed (Z = 0) when it started there. |
| Output | Binary STL in millimetres, named after your file plus the axes you used. |
| Up direction | STL and 3MF are read as Z up. OBJ, PLY and GLB are usually Y up, so they are stood upright first, the same way as in our STL editor. |
| Privacy | The file is read and mirrored on your device. It is never uploaded. |
When you need to mirror an STL
Many prints come in left and right versions: brackets, hinges, headphone hooks, shoe or glove parts, car trim, cosplay armour and keyboard halves. Designers often publish only one side, so you mirror it to get the other.
Mirroring also fixes models that were exported backwards, makes text or logos read the other way for stamps and moulds, and turns a part to fit the opposite corner of a printer or case.
Mirror vs rotate
A rotation turns the model; a mirror makes its reflection, like the left hand from the right hand. If your part only needs to face the other way, rotate it in the slicer instead. If it has to fit the opposite side, mirror it.
Mirroring on two axes is the same as one rotation of 180 degrees, so for a true left/right copy pick a single axis, usually X.
Mirroring in a slicer, Tinkercad or Meshmixer
Most slicers (PrusaSlicer, Cura, Bambu Studio, OrcaSlicer) can mirror a model on the plate, but the change stays inside that project. Tinkercad and Meshmixer can mirror too, after an account or an install.
This page gives you a mirrored STL file you can keep, share or send to a print service, with no software and no account.
Need a model to print?
Turn a photo or a short text prompt into a 3D model with AI, then mirror, scale or repair it with the free tools.