Triangulated 3D surface-mesh format used for stereolithography, CAD export, and 3D printing
File type: 3d graphics, CAD-CAM-CAE file
STL is a widely used format for storing the outer surface of three-dimensional objects as a collection of triangular facets. It is commonly used in computer-aided manufacturing, rapid prototyping, stereolithography, and consumer 3D printing.
STL files can use a readable ASCII representation or a more compact binary representation. They can be opened or imported by software such as Blender, FreeCAD, MeshLab, Autodesk Fusion, Ultimaker Cura, and PrusaSlicer.
Found 9 different file type records with the same stl filename suffix.
File type category:
3d graphics, CAD-CAM-CAE file
Date updated: October 19, 2026
STL originally stood for Stereolithography and is also commonly expanded as Standard Tessellation Language. The format was developed in the 1980s for 3D Systems stereolithography equipment and became a de facto interchange format for polygonal models used in additive manufacturing.
An STL model describes only an object's tessellated surface. Each triangular facet includes three vertex coordinates and a surface normal, although applications may recalculate the normals. Standard STL does not preserve units, color, textures, materials, assemblies, parametric features, hierarchy, cameras, or other detailed CAD information. Curved surfaces must therefore be approximated by sufficiently small triangles.
Two encoding forms are common. ASCII STL stores readable text using terms such as solid and facet, while binary STL normally contains an 80-byte header, a four-byte triangle count, and fixed-size records for each triangle. Binary files are generally smaller and faster to process, but an ASCII-looking header is not a reliable way to identify the format because binary headers may contain arbitrary text.
STL is easy for CAD and mesh applications to export, but it is not an ideal format for transferring editable CAD designs. It does not reliably define measurement units and cannot retain the original solid geometry or design history. For editable engineering data, request the native CAD file or a richer interchange format such as STEP or IGES when available. Compatible software on Windows, macOS, and Linux includes Blender, FreeCAD, and MeshLab; slicers such as Ultimaker Cura and PrusaSlicer also import it. On Windows, the extension may additionally be associated with a Certificate Trust List, which is unrelated to 3D models.
To open an STL model, install a compatible 3D viewer, CAD application, mesh editor, or 3D-printing slicer and choose its Open or Import command. On Windows, common choices include 3D Viewer, Blender, FreeCAD, MeshLab, and Ultimaker Cura. On macOS and Linux, Blender, FreeCAD, MeshLab, PrusaSlicer, and Ultimaker Cura can open or import the format.
If the model is too large, too small, inside out, or incomplete, check the import scale and units, then repair the mesh if necessary. Applications usually detect ASCII and binary files automatically, although some provide separate import options. A file associated with a Windows Certificate Trust List should be opened by certificate-management software rather than a 3D application.
To convert an STL file, import it into a desktop application such as Blender, FreeCAD, MeshLab, or Autodesk Fusion, verify its scale and orientation, and export it as OBJ, PLY, 3MF, or another supported mesh or CAD format. STL can also be exported from many CAD programs for use in a slicer. Slicers can process STL into printer-specific G-code, although G-code is a toolpath rather than a 3D model format.
Online conversion services can convert STL through a web browser, but uploading models may create privacy, file-size, or intellectual-property concerns. Conversion cannot restore information that STL does not contain, such as original CAD parameters, textures, materials, or reliable unit definitions. Inspect and, where necessary, repair the resulting mesh before using it for manufacturing.
Englishmodel/stlmodel/x.stl-binarymodel/x.stl-ascii
Software applications that can open stl files:
Microsoft Windows
Apple macOS / Mac OS X
Multiplatform
On-line services
Software applications that can edit stl files:
Microsoft Windows
Apple macOS / Mac OS X
Multiplatform
On-line services
Software capable of saving stl files:
Microsoft Windows
Apple macOS / Mac OS X
Multiplatform
On-line services
Programs for viewing stl files:
Microsoft Windows
Apple macOS / Mac OS X
Multiplatform
Software apps that create stl files:
Microsoft Windows
Apple macOS / Mac OS X
Software apps that convert stl files:
Microsoft Windows
Apple macOS / Mac OS X
On-line services
3D Transform
Software apps that import stl files:
Microsoft Windows
Apple macOS / Mac OS X
Multiplatform
On-line services
Software apps that export stl files:
Microsoft Windows
Apple macOS / Mac OS X
Multiplatform
On-line services
Software apps that print stl files:
Apple macOS / Mac OS X
Multiplatform
File type category:
Various data file
Date updated: July 30, 2018
Record marked as obsolete and not updated for a long time.
The stl file extension is associated with the Adobe Fireworks a bitmap and vector based pictures editing software for Microsoft Windows and Apple Mac.
The stl file stores style library.
Adobe Fireworks is obsolete product.
Use Adobe Fireworks to work with *.stl files.
Probably cannot be converted to other formats.
Software applications that can open stl files:
Microsoft Windows
Apple macOS / Mac OS X
Software apps that create stl files:
Microsoft Windows
Apple macOS / Mac OS X
Software applications that handle other tasks involving stl files:
Microsoft Windows
Apple macOS / Mac OS X
File type category:
Source code and script file
Date updated: July 24, 2018
The stl file extension is associated with the Microsoft Visual C++, an integrated development environment for apps developed in C/C++ programming language.
The .stl file contains standard template library.
Use compatible tools to work with *.stl files.
Templates are used to produce new projects in the original program.
Software applications that can open stl files:
Microsoft Windows
Software applications that can edit stl files:
Microsoft Windows
Software capable of saving stl files:
Microsoft Windows
Software apps that create stl files:
Microsoft Windows
File type category:
Various data file
Date updated: March 27, 2019
Record marked as obsolete and not updated for a long time.
The stl file extension is associated with the ClarisWorks (AppleWorks) an office suite for Microsoft Windows and Apple Mac OS and Mac OS X operating systems. The .stl file stores various data used for internal purposes of the ClarisWorks.
ClarisWorks is obsolete product.
Software applications that handle other tasks involving stl files:
Apple macOS / Mac OS X
File type category:
Document file
Date updated: March 21, 2019
The stl file extension is also used for EBU-standard open and teletext file format. Used in SoftNI solutions. No further information could be found.
Subtitler Suite is subtitling solution for Microsoft Windows.
Probably not meant to be accessed by the user.
Probably cannot be converted to anything else.
Software applications that can open stl files:
Microsoft Windows
Software applications that can edit stl files:
Microsoft Windows
Software capable of saving stl files:
Microsoft Windows
Software apps that create stl files:
Microsoft Windows
Software applications that handle other tasks involving stl files:
Microsoft Windows
File type category:
Settings, options, themes or skins file
Date updated: July 29, 2019
Record marked as obsolete and not updated for a long time.
The stl file extension was used by Micrografx Designer.
Micrografx was acquired by Corel. The STL file format is now probably used by iGrafx Designer.
The stl files contain style sheets.
Use compatible tools to work with *.stl files.
Probably cannot be converted to anything else.
Software applications that can open stl files:
Microsoft Windows
iGrafx Designer
Software apps that create stl files:
Microsoft Windows
iGrafx Designer
Software applications that handle other tasks involving stl files:
Microsoft Windows
iGrafx Designer
File type category:
Game file
Date updated: December 5, 2018
The stl file extension is also associated with the Korean MMORPG (massively multiplayer online role-playing game) game for Microsoft Windows called ROSE Online.
This type of stl file stores various game data for ROSE Online.
You cannot directly open this type of resource files.
Game files are rarely converted to anything else. At best they can be extracted for individual resources.
Software applications that handle other tasks involving stl files:
Microsoft Windows
File type category:
Various data file
Date updated: October 24, 2018
Record marked as obsolete and not updated for a long time.
The stl file extension is associated with the SPEFO (A Simple, Yet Powerful Program for One-Dimensional Spectra Processing) for MS-DOS operating system.
The stl file stores spectra analysis file is used by SPEFO.
Software applications that handle other tasks involving stl files:
Microsoft MS-DOS
File type category:
Various data file
Date updated: November 2, 2018
Record marked as obsolete and not updated for a long time.
The stl file extension is also related to the Win2020 a screen subtitling systems application for Microsoft Windows operating system. This type of .stl file stores screen subtitles.
The Win2020 seems to be obsolete product without support from developer.
Although a little outdated format, some subtitle editors can still work with .stl formats.
Subtitles can be typically converted between various formats.
Software applications that can open stl files:
Microsoft Windows
Swift Create
Software applications that can edit stl files:
Microsoft Windows
Swift Create
Software capable of saving stl files:
Microsoft Windows
Swift Create
Software apps that convert stl files:
On-line services
Software apps that import stl files:
Microsoft Windows
Software apps that export stl files:
Microsoft Windows
online = can be converted online at 101convert.com
Online conversions and file conversion information are provided by 101convert.com.
