OBJ to STL Converter for Private, 3D Print-Ready Files
Convert OBJ 3D object files into compact binary STL meshes directly in your browser. No upload, no account, and no software installation.
Binary STL output
OBJ geometry and coordinates are exported. MTL materials, textures, and colors are not stored in STL.
No files selected
Conversion runs locally in your browser. Your OBJ files never leave this device.
How to convert OBJ to STL online
Turn an OBJ 3D model into a downloadable STL mesh in three steps, with all processing kept on this device.
Choose OBJ files
Select up to 10 .obj 3D object files, with a maximum size of 100 MB for each file.
Convert in your browser
Select Convert to STL. The browser parses faces and vertices, then creates binary STL triangle data locally.
Download the STL
Download converted files individually or package multiple completed STL files in one ZIP archive.
OBJ to STL conversion settings
The converter reads OBJ geometry and writes a compact binary STL for slicers and other mesh workflows.
| Control | Setting | Effect |
|---|---|---|
| Processing | Local browser | The OBJ file never needs to be uploaded to a conversion server |
| STL encoding | Binary | Creates a smaller file than ASCII STL for the same triangle geometry |
| Geometry | Faces and coordinates | Triangulates supported OBJ faces and writes the resulting surface mesh |
| Batch limit | 10 files | Converts a queue and offers a ZIP download when multiple files finish |
OBJ vs STL for 3D printing
OBJ can reference materials and textures, while STL focuses on the triangle surface used by most 3D-printing slicers.
| Characteristic | Source | Output |
|---|---|---|
| Primary use | 3D interchange, rendering and editing | Slicing, manufacturing and surface geometry |
| Geometry | Vertices, faces, normals and texture coordinates | Triangle vertices and facet normals |
| Materials | Can reference an external MTL file | Not supported |
| Textures and colors | Can reference image textures | Not stored in standard STL |
| Units | No required unit metadata | Unitless; slicer import settings determine scale |
What OBJ to STL conversion preserves and removes
The format change preserves mesh geometry, but STL cannot store every feature associated with an OBJ model.
Geometry is the conversion target
Vertex coordinates and supported polygon faces become STL triangles. Object names, groups and other scene organization are not represented in STL.
MTL files and textures are removed
Standard STL has no material or texture channels, so referenced .mtl files, image maps and OBJ colors are not included.
Check scale before slicing
OBJ and STL do not reliably declare real-world units. Confirm millimeters, inches or another intended scale when importing into your slicer.
Mesh defects remain
Conversion does not close holes or fix non-manifold edges, intersecting shells, inverted faces or thin walls. Inspect and repair the STL when needed.
Related 3D file converters
Choose another 3D target format or continue preparing files for your workflow.
OBJ to STL converter FAQ
How do I convert OBJ to STL?
Choose one or more OBJ files above, select Convert to STL, then download each binary STL or save multiple results as a ZIP.
Is this OBJ to STL converter free?
Yes. You can convert OBJ files within the displayed size and batch limits without payment or account registration.
Are my OBJ files uploaded?
No. OBJ parsing and STL generation run locally in your browser, so your model does not leave your device.
Can I use the converted STL for 3D printing?
Yes. Common slicers accept STL, but inspect scale, orientation, wall thickness and watertight geometry before printing.
Are OBJ textures, colors and MTL materials preserved?
No. Standard STL stores triangle geometry only, so external MTL materials, image textures, texture coordinates and colors are not included.
Does converting OBJ to STL repair the mesh?
No. Conversion changes the file format without fixing holes, non-manifold edges, self-intersections, inverted faces or other topology problems.
Why is my STL the wrong size after conversion?
OBJ and STL are effectively unitless in many workflows. Choose the intended import units or adjust scale in your slicer before printing.
Is binary STL better than ASCII STL?
Both store the same triangle geometry. Binary STL is usually much smaller and faster to load, so this converter generates binary output.
Can I batch convert OBJ to STL?
Yes. Add up to 10 OBJ files, convert the queue, then download them separately or combine completed STL files in a ZIP.
Can I convert OBJ to STL on Mac or Windows?
Yes. The tool works in a modern browser on macOS, Windows, Linux and supported mobile devices without installing desktop software.
Convert your OBJ model to STL
Create a private binary STL in your browser, then inspect the result in your preferred slicer.
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