The STL file format was purpose-built in the late 1980s to be a file format for some of the world’s earliest SLA 3D printers. Fast forward to today, you’d be hard-pressed to find a 3D printing or modeling program that isn’t capable of at least importing an STL file.
That being said, every industry evolves, and many in the CAD industry have created their own unique and sometimes proprietary file formats. This can pose a problem if you find a really cool 3D object that you’d like to download and print.
This is why converting your 3D model over to the STL file format can be so convenient. Once it’s converted, you don’t have to worry about it not working with your slicer or 3D editor. If converting your files to STL is right for you, keep reading for a variety of both online and offline options that’ll make the conversion process a cinch.
Considerations
Rather than compiling a complete list of all STL compatible file converters out there, we picked the best tools based on a couple of guidelines. The first requirement is that the 3D model file converter must be easy to use. This encompasses the simplicity of the user interface and how easy it is to install or run through your browser.
The second guideline considered is what type of features the tool offers. For example, how many input formats does it offer, is there a maximum file size that can be converted, and is there the option to convert many files in bulk? Most of the options included support a high number of file formats, yet when that’s not the case, we specify what makes them stand out and justify their being part of the list.
With these considerations in mind, let’s jump into our list!
Online
The following STL file converters are online-only tools that don’t require installation on your computer but do require an active internet connection. Many of the choices on this list are very simple and straightforward to use, but they may not be the fastest choice if you have many files to convert.
AnyConv
AnyConv is an online platform that converts many different file types across many different categories and use cases. The 3D file converters on this platform are split into two sections: Mesh converters and CAD converters.
The versatility of conversion combinations is a huge plus, but be warned that uploads are limited to 50 MB.
- Supported file formats: Many different formats, including DXF, OBJ, and STL
- Operating system: Browser-based (mobile-friendly)
- Cost: Free
Aspose
Aspose is another online file converter that supports over 20 3D model files, including the STL format, and allows you to easily convert them over the internet. With this online option, you can upload multiple files directly from your computer, a weblink, or a Google Drive or Dropbox folder.
The Aspose website also has other features besides file conversion, like file repairing, watermarking, lithophane creation, and more.
- Supported file formats: 20+ file types including 3DS, DAE, and FBX
- Operating system: Browser-based (mobile-friendly)
- Cost: Free
Bear File Converter
Bear File Converter is another good way to quickly get a 3D model converted into STL format. The interface is simple and straightforward. Like AnyConv, Bear File Converter has a maximum file upload size of 50 MB.
- Supported file formats: 45 file types, including BLEND, OBJ, and STL
- Operating system: Browser-based (mobile-friendly)
- Cost: Free
Makexyz
In addition to their 3D printing sales service, Makexyz offers a simple and straightforward OBJ to STL file converter on their website. What makes this particular converter stand out is that you can upload very large OBJ files to their converter for free (we tested a file over 200 MB in size).
- Supported file formats: OBJ
- Operating system: Browser-based (mobile-friendly)
- Cost: Free
FabConvert
Next up, we have FabConvert, another fast and free online converter. This easy-to-use converter makes it simple to convert between a wide variety of different file types, and new formats are consistently being added. Since the tool supports bulk uploads, you can convert up to 20 files at a time. Simply drag and drop your files into the converter, click “Convert!”, and they will be ready to go!
- Supported file formats: 25+ file types, including BLEND, MAX, and OBJ
- Operating system: Browser-based (mobile-friendly)
- Cost: Free
Meshconvert
Meshconvert is a free online converter that supports many different 3D formats. Although it lacks bulk file conversion, it does have support for some unique formats, such as MD3 and MDL, which are used for 3D video game models.
- Supported file formats: 35+ file types including 3DS, DXF, and PLY
- Operating system: Browser-based (mobile-friendly)
- Cost: Free
SwiftConverter
You can use the 3D file converter on the SwiftConverter platform to change from a variety of different file types to STL. The platform functionality and user interface are pretty straightforward, allowing you to simply drag and drop a 3D file to work on it.
While it doesn’t offer the highest number of supported file formats, it’s worth mentioning that files can be up to 100 MB in size – plenty of converters are limited to 50 MB.
- Supported file formats: Six file types, including 3DS, 3DP, and OBJ
- Operating system: Browser-based
- Cost: Free
Tinkercad
While it’s more of a designing program, Tinkercad can be used as an online-only file converter.
It only supports converting OBJ and SVG file formats, yet users of the platform can also take advantage of the free data storage to save their conversion for future reference.
- Supported file formats: OBJ and SVG
- Operating system: Browser-based
- Cost: Free
Offline
While they may not be as convenient or quick to use as some of the online converters suggested earlier on our list, users who have large numbers of files to convert, are working on the go, or are concerned about sharing their 3D files online, should consider these offline options.
Blender
Blender is one of the most popular names in the 3D modeling, graphic design, and animation industries. The open-source, all-in-one design platform offers an expansive list of 2D, 3D, and video design tools, like sculpting, after effects, and more.
Although the program isn’t as CAD-focused as applications like Fusion 360, Blender supports STL files, allowing you to import, export, and convert models to and from the format. Currently, you can export an STL import to many different file formats, and more are available through public and community add-ons.
- Supported file formats: 14+ file types, including PLY, OBJ, DAE, and FBX
- Operating systems: Linux, MacOS, Windows, mobile-friendly
- Cost: Free
CAD Exchanger
Primarily focused on professional clients, CAD Exchanger is a downloadable and offline program dedicated to converting a wide range of design formats, including STL files. You can check out CAD Exchanger’s conversion diagram to see which imports, exports, and conversions are possible.
Compatible with Linux, MacOS, and Windows, CAD Exchanger is an extremely versatile application. While it does cost close to $600 per year, the program also comes with CAD-related features, like the “Cut” and “Explode” tools. You can read more about the program in our article about CAD Exchanger.
- Supported file formats: Over 15 formats supported for STL conversion, and 30 formats for other conversions
- Operating systems: Linux, MacOS, Windows
- Cost: $590 per year (free trial available)
Fusion 360
Fusion 360 by Autodesk is a robust program for advanced design, computer-aided manufacturing, simulation, and much more. While not explicitly made for file conversion, users who are already subscribed, or those who are willing to sign up for the free trial, can get access to convert 35+ file formats.
- Supported file formats: 35+ file formats, including CAM360, F3D, and STEP
- Operating systems: Windows, MacOS
- Cost: ~$545/year (limited free version available for personal use)
i3DConverter
i3DConverter is both a file converter and a 3D object file viewer that supports over 800 different file formats. Just be sure to check the table to ensure that it can both load and save the file types you need.
This robust piece of software can be installed on Linux, Mac, and Windows. Just be aware that it looks like buying the Windows license may not give you access to the Mac and Linux versions of the tool.
- Supported file formats: 800+ file types, including CAD, OBJ, and PLG
- Operating systems: Linux, MacOS, Windows
- Cost: $50
Microsoft 3D Builder
While not specifically designed to be a file converter, Microsoft 3D Builder can be installed on any Windows 10 computer to quickly convert five different 3D file types to STL. While it lacks batch processing, Microsoft 3D Builder is one of the few offline tools on the list that can be installed without administrator rights on a Windows PC.
For more about the program, check out our article on it.
- Supported file formats: Five file types, including OBJ, 3MF, and PLY
- Operating system: Windows
- Cost: Free
SketchUp Pro
While the free personal version of SketchUp is a great way for modelers to experiment with its intuitive user interface, subscribers to SketchUp Pro can take advantage of its compatibility.
It supports 20 different file formats for importing 3D files and exporting them to STL.
- Supported file formats: 20 file types, including DXF, OBJ, and KMZ
- Operating systems: Windows and MacOS
- Cost: ~$320/ year
Spin 3D
Spin 3D is a free, offline batch 3D model conversion tool for Windows. This software allows you to select, preview, and convert large groups of 3D files very quickly. Like with other offline converters, Spin 3D requires administrator rights to install.
- Supported file formats: Around 50 different file types, including 3DP, 3DS, and 3MF
- Operating system: Windows
- Cost: Free
License: The text of "The Best STL File Converters (Many Are Free)" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.