Free online tool

View STL files in your browser.

Drop an STL file below to open it instantly. Sculpty's free STL viewer renders the mesh with three.js right in your browser, so you can orbit, zoom and inspect a model before printing it — your file never leaves your computer.

Drop your STL file here
or click to browse — it opens right here in your browser, nothing is uploaded
.stl
Why this tool

Free, private, in the browser.

Instant, private preview

The STL is parsed locally in your browser. Nothing is uploaded to a server, so even confidential parts stay on your machine.

Binary and ASCII STL

Both STL flavors open the same way — the viewer detects the encoding automatically.

Full 3D navigation

Orbit, pan and zoom with the mouse, snap to standard views with the view cube, and double-click to refit the model.

No account, no watermark

The viewer is completely free. No signup wall, no export watermark, no file-size teasing.

How it works

Three steps, no setup.

01
Drop your STL

Drag the .stl file into the drop zone above, or click to browse your computer.

02
Inspect the mesh

Orbit with the left mouse button, pan with the right, zoom with the scroll wheel.

03
Check before printing

Look for holes, flipped normals or broken geometry before sending the file to your slicer.

What is an STL file?

STL (stereolithography) is the de-facto standard mesh format for 3D printing. It describes a model as a soup of triangles — no color, no materials, no units — which makes it simple, universal and supported by every slicer. Because STL stores only geometry, a viewer like this one is the fastest way to sanity-check a download from Thingiverse, Printables or a client before committing printer time.

Why view STL files online instead of installing software?

Desktop tools like Blender or MeshLab are powerful but heavy for a quick look. This viewer opens in one click, works on any laptop including Chromebooks, and — unlike many "online viewers" — does the rendering client-side with three.js instead of uploading your file to a server. That means it is faster for large meshes and safe for parts you cannot share.

Questions

Answered, plainly.

Is this STL viewer really free?+

Yes. The viewer is a free tool from Sculpty — no signup, no credits, no watermark. Sculpty makes money from its AI text-to-3D studio, not from viewing files.

Is my STL file uploaded to a server?+

No. The file is read with the browser's File API and rendered locally with three.js. It never leaves your computer, which also means there is no file-size upload limit — only your device's memory.

Can I open large STL files?+

Yes, within your device's memory. Meshes with several million triangles typically load fine on a modern laptop; extremely dense scans may take a few seconds to parse.

Can I convert the STL to another format?+

Yes — use the free STL to OBJ or STL to GLB converters linked below. They run in the browser too.

Can I create an STL from scratch?+

You can. Sculpty's studio generates 3D models from a text prompt and exports STL, OBJ, GLB, FBX and USDZ — try it if you need a model rather than already having one.

More free tools
OBJ ViewerSTL to OBJ ConverterSTL to GLB ConverterAll free tools →
Sculpty studio

Don't have a model yet? Generate one.

Type a prompt, get a textured 3D model in about a minute — then download it as GLB, STL, OBJ, FBX or USDZ.

Generate a model from text →