Scale / Resize an STL File
Resize a 3D model by a factor, to an exact target dimension, or fix a model that came out 25.4× too small or too big because of inch/millimeter confusion.
How it works
- 1Drop the file
The current dimensions are shown.
- 2Choose factor or target size
Use the inch/mm presets for unit problems, or type the exact height you need.
- 3Apply and download
Scaling is uniform so proportions are preserved.
Details
Because STL has no unit, models made in inches show up 25.4× too small in a millimeter slicer, and models exported in meters 1000× too small. Scaling the file once fixes it for every slicer and every future print rather than remembering to correct it each time.
Scaling to a target size is the quick way to make a miniature exactly 32 mm tall or a phone stand exactly as wide as your phone. The tool keeps the model centered where it was.
Accepted formats: STL, OBJ, 3MF, PLY, GLB, glTF, STEP, STP
Frequently asked questions
More STL tools
- Get the Dimensions of an STL File
Drop an STL (or any 3D file) to read its exact width, depth and height, bounding box, volume, surface area and triangle count. Runs in your browser, nothing is uploaded.
- Reduce STL File Size (Simplify Mesh)
Cut the triangle count of an STL file by a chosen percentage while keeping the shape. Useful for oversized 3D scans, slow slicers and upload limits. Runs locally in your browser.
- Convert STL ASCII to Binary (and back)
Convert a text (ASCII) STL into the compact binary STL that slicers load faster, or the other way round for inspection. Binary files are typically 4–5× smaller.
- Repair an STL File
Weld duplicate vertices, remove degenerate triangles, recompute normals and get a report of open and non-manifold edges before you slice. Basic repair for common export problems.
- STL File Info: Binary or ASCII, Triangle Count, Header
Inspect what is inside an STL file: encoding, header text, triangle count, bounding box and whether the mesh is closed. Handy before sending a file to a print service.