Free · in your browser · nothing uploaded
Convert OBJ to STL free, in your browser
Take a mesh from Blender, ZBrush, a scanner or a model store and turn it into a compact binary STL your slicer will accept — sized and oriented for printing.
- Binary STL, much smaller than text OBJ
- All objects and groups merged
- Fit to a size in mm
- Private: runs on your device
Updated by the Kenerate AI team
On this page
Quick answer
Updated
How do you convert OBJ to STL?
To convert OBJ to STL, load the .obj, triangulate its faces and write them to an STL file. Kenerate's free converter does it in your browser: drop the OBJ, preview it, fit the longest side to a size in millimetres and turn it Z-up, then download a binary STL. Materials and UVs are dropped. Nothing is uploaded.
Key facts
- Price
- Free, no account
- Converts
- Wavefront OBJ → binary STL
- Faces
- Quads and n-gons triangulated
- Dropped
- Materials (.mtl), UVs, smoothing groups
- Scale
- Keep units or fit longest side to 25–200 mm
- Privacy
- Converted locally — no upload
Why this tool
Why turn an OBJ into an STL
Most slicers read OBJ, but STL is smaller, simpler and accepted by every print service and printer workflow.
Also
What else it does
Size it for print
OBJ has no units. Fit the longest side to the size you want and print without rescaling in the slicer.
Check before printing
The Clay and Wire views show holes, thin walls and messy scan areas before you waste filament.
How it works
How OBJ becomes STL
All on your device.
Parse
Vertices and faces are read from the OBJ text; quads and n-gons are split into triangles.
Merge
Objects and groups are combined in their original positions.
Scale and orient
Optionally fit to a size in millimetres and turn Z-up.
Write
A binary STL is generated and downloaded.
How to
How to use the OBJ to STL Converter
- Time needed
- Steps
- 4 steps
Step 1
Open the OBJ
Drop your .obj onto the box above, or try the sample mug.
Step 2
Preview
Orbit it and check the triangle count.
Step 3
Set options
STL is selected. Choose a size in mm if you need one; keep Z-up for slicers.
Step 4
Download
Click Download STL.
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Text, photo or multi-view to a textured GLB, nine engines, the viewer & lighting, compare engines, gallery, download & chat
Chapters
Who uses it
Who converts OBJ to STL
Blender and ZBrush users
Send a sculpt or model to the printer.
3D scanning
Turn a cleaned scan into a printable file.
Print services
Normalise orders to one format.
Students and makerspaces
Convert class files without installing anything.
Compare
OBJ vs STL
Both are plain triangle meshes at heart; OBJ carries more around them.
| OBJ | STL | |
|---|---|---|
| Encoding | Text | Binary (or text) |
| Faces | Triangles, quads, n-gons | Triangles only |
| UVs and materials | Yes (UVs in file, materials in .mtl) | No |
| Units | None | None |
| Typical use | Moving meshes between 3D apps | 3D printing |
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.
| .obj · OBJ | .stl · STL | |
|---|---|---|
| Full name | Wavefront OBJ | Stereolithography |
| Made by | Wavefront Technologies, 1980s | 3D Systems, 1987 |
| Kind | Plain-text mesh | Triangle mesh (binary or ASCII) |
| Holds | Vertices, faces, UVs and normals, Materials via a separate .mtl file | Triangle surfaces, Facet normals |
| No | Animation and rigs, Embedded textures | Colour and textures, Units, Materials |
| Best for | Moving static meshes between 3D apps | 3D printing — every slicer opens it |
| Opens in | Blender, Maya, 3ds Max, ZBrush, most slicers | Cura, PrusaSlicer, Bambu Studio, OrcaSlicer, Blender |
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 OBJ to STL converter
Illustrative examples of typical workflows, not customer reviews.
Digital sculptor
A sculptor can export a model from their 3D app as OBJ and turn it into a binary STL sized in millimetres for printing.
3D scanning hobbyist
A scanning hobbyist can turn a cleaned scan saved as OBJ into a printable STL without installing anything.
Makerspace student
A student can convert class OBJ files to STL on a shared computer and print them on the makerspace printer.
FAQ
OBJ to STL Converter questions
7 questions
Is OBJ to STL conversion free?
Yes. It runs in your browser with no account or watermark.
Link to this answerIs my OBJ uploaded?
No — it's converted on your device.
Link to this answerDo I need the .mtl file?
No. STL can't store materials, so only the .obj is needed.
Link to this answerWhat happens to quads?
They're split into two triangles each. The shape doesn't change.
Link to this answerMy STL is the wrong size — why?
OBJ has no units. Choose “Fit longest side to” a size in millimetres before downloading.
Link to this answerCan I keep colours?
Not in STL. Convert to 3MF or GLB if colour matters.
Link to this answerHow do I convert OBJ to STL in Blender?
Import the OBJ with File → Import → Wavefront (.obj), select the model, then use File → Export → STL (.stl) and tick Selection Only if the scene has other objects. Check the scale first, because OBJ has no units. Or skip Blender: drop the OBJ here and set the size in millimetres.
Link to this answerIn depth
OBJ to STL Converter, explained
What the formats really store, what changes when you convert, and how to avoid the usual print and import problems.
Do slicers need STL?
Not always — PrusaSlicer, Cura and others read OBJ directly. STL is still the safest choice for print services, older tools and printer-specific software, and its binary form is compact [1].
Keep going
Other 3D viewers and converters
- 3D Model ConverterAny format to STL, OBJ, GLB, 3MF, USDZ
- 3MF to STLSlicer projects to plain STL
- GLB to STLAI models ready to print
- STL to OBJPrint files into 3D apps
- STL to 3MFUnits and a modern print format
- GLB to OBJglTF into classic 3D apps
- FBX to OBJStatic meshes from FBX
- FBX to STLGame assets to printable files
Try the OBJ to STL Converter
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