STL Editor Online — Resize, Rotate & Measure STL Files

The file was exported in inches. STL stores raw coordinates with no unit field, and every slicer — Cura, PrusaSlicer, Bambu Studio — reads one unit as one millimeter, so an inch-based model lands at 1/25.4 scale. Load the file here, set the source unit to inches, and export; the geometry is multiplied by 25.4 on the way out.

No. Scaling and rotation move existing vertices; no triangles are added or removed, so surface detail is preserved exactly. Every edit is recomputed in double precision from the original geometry — repeated tweaks never accumulate rounding error — and facet normals are regenerated on export, so the slicer shades non-uniform scales correctly.

No — this editor only scales, rotates, repositions, and measures. If your mesh has holes, non-manifold edges, or flipped faces, run it through Meshy's free STL Repair tool first, then come back to resize and orient it. The repair takes about a minute and needs no 3D modeling skills.

This tool imports and exports STL only. For format changes, use Meshy's free file converter — it handles STL to 3MF, PLY, OBJ, GLB, and more. 3MF is worth the switch for printing: unlike STL, it stores real units, so the inch-to-millimeter problem disappears entirely.

Just load it and download — this editor accepts either encoding and always writes binary, so the file you get back is the converted one. Binary is the compact form: the same mesh takes roughly a fifth of the space, because each triangle costs a fixed 50 bytes instead of a few hundred characters of text. Both encodings describe identical geometry, so nothing is lost. Note that the 100 MB limit applies to the file you upload, and an ASCII file is about five times larger than the binary version of the same mesh.

Not a file you upload here. This editor changes the size, orientation and position of any STL, never its shape. To change the shape with AI — remove, add or replace a part — generate the model in Meshy and edit it with Meshy Edit, which currently works on models generated in Meshy rather than uploaded files. Download the result as STL and bring it back here to size it for your printer.

This editor adjusts geometry you already have: scale, rotate, center and measure any STL, free in your browser with no account. Meshy Edit changes what the model is: circle a region of a model you generated in Meshy and describe the change, such as swapping boots for sneakers. It runs in the Meshy workspace, needs an account and uses credits. Many people use both — generate, reshape with Meshy Edit, then export the STL and finish it here. For a wider comparison, see this roundup of 3D model editors.