Free · no account · nothing uploaded
Free online STL viewer
Drop an .stl and look at it from every side before you slice it. Check the triangle count, the real size and the surface in clay or wireframe — then save it as 3MF, OBJ or GLB if you need to.
- Binary and ASCII STL up to 200 MB
- Clay, wireframe and normals shading
- Triangles, vertices and size at a glance
- Your file never leaves your device
Updated by the Kenerate AI team
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Quick answer
Updated
What is an STL viewer?
An STL viewer is a tool that opens a .stl 3D-printing file so you can see the model without a slicer or CAD program. Kenerate's free STL viewer runs in your browser with three.js: switch to clay or wireframe and check its triangle count and size. The file is read on your device and never uploaded.
Key facts
- Price
- Free, no account
- Opens
- Binary and ASCII STL up to 200 MB (plus OBJ, FBX, GLB, 3MF, PLY)
- Views
- Textured · Clay · Wire · Normals, grid, auto-rotate
- Shows
- Triangles, vertices, meshes, bounding-box size
- Save as
- STL, 3MF, OBJ, GLB, PLY, USDZ
- Privacy
- Parsed locally in the browser — no upload
Why this tool
Check a print file before it costs you filament
STL has no colour and no units, so what matters is the shape. These views are built to show the shape clearly.
See the surface, not the shading
Clay mode lights the mesh evenly so dents, stair-stepping and thin walls stand out; wireframe shows how dense the triangles are and where a scan or AI model got messy.
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Measurements and counts
Triangle and vertex counts tell you whether the file will choke a slicer; the bounding box shows its size in the file's own units.
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Also
What else it does
Both STL flavours
Binary STL (the usual kind) and ASCII STL both open. Facet normals in the file are kept for shading.
Any device
Works in Chrome, Edge, Firefox and Safari on desktop, tablet and phone — WebGL is the only requirement.
Screenshot it
Save a PNG of the current view for a listing, a print log or a message to a client.
Hand it on
Need units or a modern print format? Save the same model as 3MF in millimetres, or as OBJ / GLB for other apps.
How it works
What happens when you drop an STL
All four steps run on your computer. The page never sends the file anywhere.
Read
The file is read into memory and checked for the binary STL header or ASCII “solid” text.
Parse
Every facet becomes a triangle with its normal; STL has no materials, so a neutral grey is applied.
Frame
The model is centred, placed on the floor and scaled to fit the view — your file is not changed.
Inspect
Orbit, switch shading, read the stats or save it in another format.
How to
How to use the STL Viewer
- Time needed
- Steps
- 4 steps
Step 1
Open the file
Drag your .stl onto the box above, or click it to choose a file. You can also try the sample dragon.
Step 2
Look around
Drag to orbit, scroll or pinch to zoom, right-drag to pan. Turn auto-rotate off to hold a view.
Step 3
Check the surface
Switch to Clay for even lighting or Wire to see the triangles. Read the triangle count and size underneath.
Step 4
Save or convert
Take a PNG screenshot, or pick 3MF, OBJ or GLB and download a converted copy.
Watch the tour · 1:48
Text, photo or multi-view to a textured GLB, nine engines, the viewer & lighting, compare engines, gallery, download & chat
Chapters
Who uses it
Made for people who print
3D printing hobbyists
Look at a download from Printables or Thingiverse before you queue it.
Print farms and services
Preview a customer's file and its size on any machine, without installing a slicer.
Teachers and students
Open class files on school Chromebooks where you can't install software.
Designers and makers
Share a quick screenshot of a part, or check an export from CAD.
File formats
The formats this tool reads and writes
What each file can hold, what it can't, and where it opens. Facts link to the format's own spec or reference page.
| .stl · STL | .3mf · 3MF | .obj · OBJ | |
|---|---|---|---|
| Full name | Stereolithography | 3D Manufacturing Format | Wavefront OBJ |
| Made by | 3D Systems, 1987 | 3MF Consortium, 2015 | Wavefront Technologies, 1980s |
| Kind | Triangle mesh (binary or ASCII) | ZIP package with XML | Plain-text mesh |
| Holds | Triangle surfaces, Facet normals | Meshes with units (millimetres), Colours and materials, Several objects and build plates | Vertices, faces, UVs and normals, Materials via a separate .mtl file |
| No | Colour and textures, Units, Materials | Animation | Animation and rigs, Embedded textures |
| Best for | 3D printing — every slicer opens it | Modern 3D printing and multi-colour prints | Moving static meshes between 3D apps |
| Opens in | Cura, PrusaSlicer, Bambu Studio, OrcaSlicer, Blender | Bambu Studio, PrusaSlicer, OrcaSlicer, Cura, Windows 3D Builder | Blender, Maya, 3ds Max, ZBrush, most slicers |
No file yet?
Make the model first — from one photo
Every sample in the tool above began as a single picture and was turned into a 3D model in the Kenerate 3D Studio. The engine is named on each one.
Example uses
How creators use the STL viewer
Illustrative examples of typical workflows, not customer reviews.
3D printing hobbyist
A hobbyist can look at a downloaded model from every side before queueing it on the printer.
Teacher
A teacher can open class files on school laptops where installing software isn't allowed.
Print service
A print service can preview a customer's file and its size on any machine before quoting.
FAQ
STL Viewer questions
10 questions
Is this STL viewer free?
Yes. It's free with no account, no watermark and no daily limit, because the work happens in your own browser.
Link to this answerIs my STL file uploaded?
No. The file is read by JavaScript on your device and drawn with WebGL. Only the sample model is downloaded from our server.
Link to this answerWhy is my STL grey?
STL stores only triangles — no colour, textures or materials — so every viewer shows it in a neutral material. If you need colour, use 3MF, OBJ with MTL, or GLB.
Link to this answerWhat size is my model?
STL has no units. The size shown is in the file's own units; most slicers assume millimetres. To set a size, choose 3MF and “Fit longest side to” a value in millimetres.
Link to this answerCan I open STL files on a phone?
Yes. The viewer works in mobile Safari and Chrome. Very large files (100 MB+) may be slow on older phones.
Link to this answerDoes it open ASCII STL?
Yes, both binary and ASCII STL open. Binary files are much smaller for the same model.
Link to this answerIs this an STL viewer and editor?
It's a viewer and converter: it can rescale the model and turn it Z-up for slicers when you save to STL, 3MF or OBJ. To set exact sizes, rotate, mirror or fix inch units, open the file in the free STL editor.
Link to this answerCan I measure an STL here?
Yes, its overall size: the viewer shows the bounding-box width, depth and height in the file's own units (usually millimetres), plus triangle and vertex counts. It doesn't measure point-to-point distances — use your slicer or CAD tool for that, or set an exact size in the STL editor.
Link to this answerDoes Windows have an STL viewer?
Some Windows versions include Microsoft's 3D Viewer or 3D Builder app, which can open STL. If yours doesn't, this viewer works in Edge, Chrome or Firefox on Windows with nothing to install, and the same page works on Mac, Linux, Chromebook and phones.
Link to this answerHow do I make an STL if I don't have one?
Use the Kenerate 3D Studio to turn a photo or a text prompt into a model, then convert it to STL here. AI generation is on any paid plan or credit pack.
Link to this answerIn depth
STL Viewer, explained
What the formats really store, what changes when you convert, and how to avoid the usual print and import problems.
On this page
What an STL file actually stores
STL was created by 3D Systems in 1987 for its stereolithography printers [1]. A file is just a list of triangles (facets), each with three corner points and a normal that says which way is “out”.
That simplicity is why every slicer reads it — and why it has no colour, no textures, no units and no notion of separate parts [1]. A file that looks blue in one viewer and grey in another is the same file.
Units: the most common STL surprise
Because STL carries no units, a model drawn in inches can import 25.4× too small, and one exported in metres can appear as a speck. Slicers usually assume millimetres.
3MF fixes this by storing the unit (millimetres by default) in the file [5]. Saving to 3MF with “Fit longest side to” lets you set the real size once.
Binary vs ASCII STL
Binary STL stores each triangle in 50 bytes; ASCII writes the same numbers as text, so files are several times larger [1]. Both describe the same geometry. This viewer reads both and always writes binary.
Reading the wireframe
Even, small triangles on curved areas and large triangles on flat areas is a healthy mesh. Long sliver triangles, holes or overlapping shells can cause slicing errors — fix those in your slicer's repair tool or in Blender before printing.
Keep going
Other 3D viewers and converters
- 3D Model ViewerOpen STL, OBJ, FBX, GLB, 3MF, PLY
- GLB ViewerglTF / GLB with PBR materials
- OBJ ViewerWavefront OBJ in your browser
- FBX ViewerAutodesk FBX, no install
- 3D Model ConverterAny format to STL, OBJ, GLB, 3MF, USDZ
- 3MF to STLSlicer projects to plain STL
- GLB to STLAI models ready to print
- OBJ to STLMeshes for any slicer
Try the STL Viewer
Free and private — your files never leave your device. Want to make models with AI? That's the 3D Studio, on any paid plan or credit pack.
Tried it? Tell us how it went