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STL Size Reducer

Shrink a heavy STL to a target size with quality-preserving decimation. Set the maximum MB; we stop as soon as we hit it — if the mesh can't go smaller without breaking, we return the smallest safe result.

1
Upload STL
2
Set target MB
3
Download
📉
Drop an STL file here or click to browse
Up to 300 MB · .stl only
MB
1 MB500 MB

We aim for exactly this size. Quality-preserving quadric decimation stops as soon as the file fits. If the mesh cannot be reduced further without breaking, we return the smallest safe result.

Pick an STL file to continue.
🔒 Files are processed on our server in isolated memory and removed within 15 minutes of your download.
Server-sideProcessed server-side

This tool uses a server-side service for processing; uploaded files or requests are not kept for long-term storage.

About

Slicers, marketplaces and cloud printers often cap STL uploads at 20 – 100 MB. When a scan or a sculpt blows past the limit the usual answer is to rebuild the model from scratch. This tool does it for you: pick a maximum size in megabytes, upload the file, and we decimate the triangle mesh until the STL fits. If the model can't be reduced any further without breaking, we stop at the smallest safe version and tell you what was achieved.

How it works: we first re-export to binary STL, which is roughly 5× smaller than ASCII with identical geometry. If that alone gets you under the target, we stop there — no quality loss. Otherwise we run curvature-aware quadric edge-collapse (PyMeshLab) which keeps sharp features, holes and boundaries while dropping redundant triangles in flat regions. Watertightness is preserved when possible.

Steps: (1) drop an .stl file up to 300 MB, (2) set the target maximum size — slider accepts 1 to 500 MB, (3) click Reduce. You get back a binary STL plus a report: size before/after, triangle count before/after, whether the target was hit, whether the result is still watertight. Files are processed on our server in isolated memory and deleted within 15 minutes of your download.

Typical use cases: shrinking a 150 MB Lithophane export to the 50 MB upload limit of a print farm; pushing a photogrammetry scan under a slicer's ceiling without remeshing in Blender; trimming an organic sculpt so it loads smoothly in a viewer. Binary-in, binary-out, same orientation and scale.

How it works

  1. 1Open STL Size Reducer and choose your file or enter the required input.
  2. 2Check the settings and start the process.
  3. 3The tool creates the result with temporary server-side processing.
  4. 4Download the output or copy the result when it is ready.

FAQ

›What target sizes work best?
Any value between 1 and 500 MB. Most slicers and marketplaces cap uploads at 20 – 100 MB; 5 – 10 MB is typical for email attachments and web viewers. Go below 5 MB only if visible quality loss is acceptable.
›Will it damage my model?
The first pass is lossless (binary re-encode). If further shrinking is needed we run curvature-aware quadric decimation, which preserves sharp features, boundaries and holes. Expect visually identical results at 30 – 70% reduction; heavy reductions on scans may lose fine detail.
›What if the file can't reach my target?
We stop at the smallest size that keeps the mesh valid and return that file. The result screen tells you the actual size achieved and whether the target was hit.
›Is the result still watertight?
We try. The reducer reports watertightness before and after so you can confirm. For 3D printing you usually want a watertight result; we prefer that over hitting the exact MB target when both aren't possible.
›Maximum upload size?
300 MB. If your file is larger, export a coarser LOD from your DCC tool first.
›Are my files kept?
No. Uploads are processed in an isolated temp dir and deleted within 15 minutes of your download.
›ASCII STL supported?
Yes. The reducer converts ASCII to binary as its first step, which is already ~5× smaller with no quality loss.