How to make an STL smaller
- Drop the STL into the box above – it is reduced to 50 % automatically.
- Pick a stronger level (25 %, 10 %, 3 %) in Mesh tools and click Reduce; compare the preview.
- Download as binary STL, or as 3MF, which is zipped and often 3–5× smaller again.
How far can you go?
| Use | Typical triangle budget |
|---|---|
| FDM printing (0.4 mm nozzle) | 100k–500k |
| Resin printing, fine detail | 500k–2M |
| Importing into CAD as STEP | under 50k–100k |
| Web / AR preview | 20k–100k |
The reduction uses a quality-driven edge-collapse algorithm (meshoptimizer), which removes triangles where the surface is flat first and keeps sharp features. Read more in why STL files get so large.
Frequently asked questions
Will reducing triangles change the dimensions?
The overall size stays the same. Fine surface detail is simplified first; at very strong levels (3 %) small features can soften – check the preview.
Is it free?
Yes – up to 3 downloads a day are free, with no sign-up or watermark. Pro (free for 7 days) makes it unlimited.
Is my file uploaded?
No. The file is processed in your browser and never leaves your device.