Lightning-fast conversion
Convert in seconds with our cloud-based engine. No waiting.
Free online tool
Free Online STL to OFF Converter
Easily convert your .stl files to .off format using our powerful online 3D CAD converter—no downloads or installations required.
Encrypted uploads
Auto-delete in 24hrs
Up to 300 MB
Drag & drop your 3D files here to convert
or click to browse files
Supported formats: .stl
Don't have a file? Try a sample:
Conversion quality notes (read before converting)
- CAD → Mesh (STEP/IGES/BREP → STL/OBJ/PLY): may lose parametric features; output becomes triangles.
- Mesh → CAD (STL/OBJ/PLY → STEP/IGES/BREP): may produce surfaces/approximations depending on engine.
- If output looks broken, try converting to STEP first, then to your target format.
Explore more
Need to preview before converting?
Open CAD Viewer →Looking for ready-to-use CAD files?
Browse CAD Library →HOW IT WORKS
How to convert STL to OFF online
No downloads. No plugins. Works right from your browser.
01
Upload your STL file
Drag & drop or browse to select your .stl file
02
Select OFF as the output format
Choose OFF as your target CAD format
03
Convert and download instantly
Download your converted OFF file in one click
Why use Marathon OS 3D CAD File Converter
No installation required
Works in your browser — no downloads or plugins needed.
Handles large & complex models
Optimized for large and intricate CAD files up to 300 MB.
Secure & private
Encrypted uploads. Files automatically deleted after 24 hours.
Your files, your IP
Full file ownership stays with you. We never share your data.
Available 24/7
Convert files anytime, anywhere — no restrictions.
Privacy and file handling
Encrypted uploads + secure processing
Files are encrypted during upload and processed securely.
Automatic deletion after 24 hours
Uploads are automatically deleted after 24 hours.
File ownership stays with you
You retain full ownership of your files.
STL
Stereolithography is a widely used file format for 3D printing and computer-aided design (CAD). It is primarily used for representing 3D models in a way that can be understood by 3D printers, CNC machines, and other manufacturing technologies.
OFF
simple text-based file format used to represent 3D geometric data, particularly for storing and sharing polygonal meshes. It is often used in computational geometry, 3D modeling, and research applications, where the focus is primarily on the geometric structure of objects, rather than materials or textures.
Popular conversions.
CAD Converter Types
STEPSTL
For 3D printing and rapid prototyping
STEPIGES
For cross-platform CAD exchange
STEPOBJ
For rendering and visualization
IGESSTEP
For modern CAD compatibility
IGESSTL
For 3D printing from legacy files
STLSTEP
For reverse engineering workflows
OBJSTEP
For CAD editing from mesh files
BREPSTL
For additive manufacturing
STLOBJ
For game engines and 3D rendering
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Frequently asked questions
Find answers about converting files with Marathon OS stl to off converter.
How do I convert STL to OFF online?
Upload your STL file (.stl) to Marathon OS, choose OFF as the output format, and download the converted file in seconds — no software installation required.
Why convert STL to OFF?
Converting STL to OFF helps you move CAD data between tools, suppliers, and workflows without installing desktop software. Marathon OS handles the conversion in the cloud so you can download a OFF file in seconds.
What STL and OFF file extensions are supported?
This converter accepts .stl input files and outputs .off. Upload up to 300 MB per file.
Is the STL to OFF converter free?
Yes — converting STL to OFF on Marathon OS is completely free with no usage limits or hidden costs.
How is my data stored and secured?
Your files are encrypted during upload, processed securely in the cloud, and automatically deleted after 24 hours.
Do I need any special software or training?
No — upload your STL file and download OFF directly in your browser. No plugins or desktop CAD tools required.
Can I convert large STL models to OFF?
Yes — Marathon OS is optimized for large and complex CAD models. You can upload files up to 300 MB for STL to OFF conversion.
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