STL simplifier

Simplify STL

Reduce the triangles of a heavy model while keeping its overall shape.

1Your file

Tap to choose your fileSTL (also 3MF, OBJ or GLB) · you can drag it here. It isn't uploaded anywhere.

2Settings

Resize by Size 100 %

Side Size in mm

It scales equally on all three sides, so it doesn't get distorted.

File units

OBJ files don't say which unit they use. If the size looks wrong, change it here.

Triangles to keep 30 %

Fewer triangles = a lighter file, but the finest details are lost. For scans, 20 to 40% is barely noticeable.

Image size Background Part color

Rotate the view to the angle you want: the image comes out exactly as you see it.

What to include

"Just the shape" is lighter and enough to recover the part. Supports and skirt are never included.

Part thickness (mm)

A DXF is a flat drawing: this is the height given to every closed shape.

Stand it up (it's lying down)

This happens with files from Blender or video games, which use a different up axis.

Your printer's size

Choose a file to simplify.

Drag to rotate

How much does it cost to print?

Private: everything is calculated in your browser and nothing is uploaded.

Choose your model

STL, OBJ, 3MF, PLY or GLB, however heavy.

Choose how much to reduce

The percentage of triangles to keep; you see it in 3D instantly.

Download the STL

Lighter, ready for your slicer.

Why simplify

3D scans, photogrammetry and AI-generated models often come with millions of triangles: the file weighs hundreds of megabytes, the slicer is slow to open it and the printer can't render that much detail anyway. Reducing to 20 or 30% is barely noticeable on the printed part.

The tool merges points that are very close together and removes the leftover triangles. You see the result in 3D before downloading.

How much to reduce

Scans and AI models: 20 to 40%.
Parts with fine detail (small text, textures): 50 to 70%.
Simple models (boxes, flat parts): they gain almost nothing; they stay about the same.

Good to know

Details smaller than the merge size are lost, so it's worth checking the preview. Parts with few triangles, like ones with straight shapes, can't be reduced much without distorting.

Tips

Check fine edges in the preview before downloading.
If your slicer chokes on a scan, start at 30%.
Simplify before scaling: the result is the same and it's faster.
Keep the original file: simplifying can't be undone.

Frequently asked questions

Is quality lost?

A little: the finest details. With scans and AI models, reducing to 20–40% is barely noticeable when printed, because the printer can't render that much detail.

How heavy can the file be?

Up to about 4 million triangles; more than that doesn't fit well in the browser's memory.

Why does my model barely reduce?

Because it already has few triangles, like parts with straight shapes. There isn't much to remove without distorting it.

Is my file uploaded to the internet?

No. It's read and simplified in your browser; it isn't sent anywhere.

Why is there a download limit?

The tool is free and supported by ads. Each visit includes 5 downloads; to keep going, open the page again.