Free local 3D tool

STL Viewer Online

Open an STL file, rotate the model and inspect its shape, dimensions and triangle count. Files are read on your device, with no upload or sign-up.

Your STL preview

Open a file or try a sample to see the model here.

Inspect a real file example

Inspect a real cup STL

72.89 × 73.20 × 80 mm (file axes) · 47,326 triangles

This cup was generated in Quady3D and exported to STL. Check the inner surface and any separate pieces in your slicer before printing.

Download sample STL Back to the workspace ↑

How to inspect your STL

Open the actual file

Choose an STL up to 32 MB or load the cup sample. Drag to orbit, zoom into details and reset the camera to see the complete mesh.

Confirm units

Dimensions show X × Y × Z in source model units. STL has no unit label: a value of 80 only means 80 mm if that is the intended import unit.

Continue in a slicer

Look for detached fragments and thin features. This STL reader provides a visual inspection; it does not calculate watertightness, wall thickness or point-to-point distances.

Questions about STL Viewer Online

How do I open STL online?

Choose Open STL or drag a .stl file into the file area. After loading, drag to rotate, scroll or pinch to zoom, and use Reset camera to return to the full model.

Is the STL online viewer free, and is my file uploaded?

Viewing STL files is free and does not use generation credits or require sign-up. The selected file is parsed and displayed in your browser; its contents are not uploaded.

Does it support binary and ASCII STL?

Yes. Both STL encodings use the same file input. Each file can be up to 32 MB; complex models may use substantial memory, especially on a phone.

Are the displayed dimensions in millimeters?

The bounds show X, Y and Z in the file's coordinates. STL does not record a physical unit. Confirm whether the source uses millimeters, inches or another unit before setting the size in your slicer.

Why does my STL have no colors or textures?

This viewer treats STL as surface geometry. Textures and material colors from a GLB or OBJ are not part of the STL preview.

Does opening an STL prove that it will print?

No. You can visually review the shape, underside and small details, but this viewer does not certify watertightness, measure wall thickness or calculate supports. Check the model's scale, orientation and layers in your slicer before printing.

Free local 3D tool

STL Viewer Online

Open an STL file, rotate the model and inspect its shape, dimensions and triangle count. Files are read on your device, with no upload or sign-up.

Your STL preview

Open a file or try a sample to see the model here.

Inspect a real file example

Inspect a real cup STL

72.89 × 73.20 × 80 mm (file axes) · 47,326 triangles

This cup was generated in Quady3D and exported to STL. Check the inner surface and any separate pieces in your slicer before printing.

Download sample STL Back to the workspace ↑

How to inspect your STL

Open the actual file

Choose an STL up to 32 MB or load the cup sample. Drag to orbit, zoom into details and reset the camera to see the complete mesh.

Confirm units

Dimensions show X × Y × Z in source model units. STL has no unit label: a value of 80 only means 80 mm if that is the intended import unit.

Continue in a slicer

Look for detached fragments and thin features. This STL reader provides a visual inspection; it does not calculate watertightness, wall thickness or point-to-point distances.

Questions about STL Viewer Online

How do I open STL online?

Choose Open STL or drag a .stl file into the file area. After loading, drag to rotate, scroll or pinch to zoom, and use Reset camera to return to the full model.

Is the STL online viewer free, and is my file uploaded?

Viewing STL files is free and does not use generation credits or require sign-up. The selected file is parsed and displayed in your browser; its contents are not uploaded.

Does it support binary and ASCII STL?

Yes. Both STL encodings use the same file input. Each file can be up to 32 MB; complex models may use substantial memory, especially on a phone.

Are the displayed dimensions in millimeters?

The bounds show X, Y and Z in the file's coordinates. STL does not record a physical unit. Confirm whether the source uses millimeters, inches or another unit before setting the size in your slicer.

Why does my STL have no colors or textures?

This viewer treats STL as surface geometry. Textures and material colors from a GLB or OBJ are not part of the STL preview.

Does opening an STL prove that it will print?