5 Best Free STEP to STL Converter Software for Windows

Here is a list of Best Free STEP to STL Converter Software for Windows. STEP (Standard for the Exchange of Product Data) is an ISO standard exchange format which is used for creating and storing 3D models and respective data. STL (Stereolithography) is another 3D file format which stores three-dimensional designs and information. Now, in order to convert a STEP model to STL format, you need a 3D CAD software which supports STEP as input format and STL as output format. To help you out, I have curated this list which contains all free software which let you convert STEP to STL.

In all of these software, you need to simply import a STEP file and then convert it to STL format using the export feature. Prior to conversion, most of these software let you modify the STEP model using various design tools like mesh creation, extrude, sweep, press pull, transform, etc. Additionally, one of these even lets you batch convert STEP files to STL format. You can also set up some output configurations before saving STL file, such as data format (ASCII or Binary), tessellation settings, flip geometric normals, etc.

All in all, these are featured software which let you view, analyze, edit, create, and convert 3D models. You can work with some other 3D file formats using these software, like OBJ, 3DS, DAE, PLY, IGES, VRML, etc.

My Favorite Free STEP to STL Converter Software for Windows:

FreeCAD is a feature rich and user-friendly software to convert STEP to STL. It can be used for designing various 3D projects and converting various existing 3D models.

GOM Inspect is another good one. It provides advanced 3D model analysis tools which may come in handy.

You may also check out lists of best free STEP File Viewer with Measurement, 3DS to STL Converter Software, and STEP File Viewer Software for Windows.


FreeCAD is a free open source STEP to STL converter software for Windows, Linux, and Mac. It is a featured 3D modeling software with support to all major 3D file formats including STEP, STL, OBJ, DAE, PLY, 3DS, etc. Using it, you can easily open a 3D model in a supported format, view and analyze it, edit it if required, and then save it in a different 3D file format. Let’s see how you can convert STEP to STL using this software.

How to convert STEP to STL in FreeCAD:

  • From its File menu, click on the Open or Import option to be able to import a STEP model to this software.
  • If you want, you can now modify the STEP file according to your requirements. This can be done with the help of its various mesh designing, transformation, and other tools.
  • Finally, go to its File menu > Export option and select STL as the output format to convert STEP to STL.

Additional Features:

  • It offers specific designing tools in different workbenches as per the kind of model you want to design, such as Raytracing, Robot, Sketcher, Mesh Design, Part Design, Ship, Drawing, FEM, etc.
  • A feature rich set of viewing tools is provided in it to view a 3D model, such as standard views, orthographic views, different rending style, zoom, stereo, toggle visibility, toggle measurement, etc.
  • Few more useful tools like Scene Inspector, Measure Distance, Dependency Graph, View Turnable, Units Calculator, etc., are available in it.


It is a great 3D modeling software using which you can create, view, edit, and convert 3D models including conversion of STEP to STL.


Gmsh is a free, open source, portable STEP to STL converter software for Windows, Mac, and Linux. It is a 3D finite element mesh generator which you can also use to convert 3D models from one format to another, including STP to STL. Besides STL, you can convert STEP to a few other formats such as PLY2, WRL, X3D, Images, etc.

How to convert STEP to STL in Gmsh:

  • Launch this portable software and click on its File > Open option to import a STEP file to it.
  • Now, if there are some changes you need to make to the model, you can do that by using available tools. For example, add box, cone, sphere, wedge, point, line, curve, disk, etc., transform (translate, rotate, scale, symmetry), extrude, boolean, mesh editing tools, etc.
  • Next, click on its File > Export feature and set the output format to STL to be able to convert STEP to STL. Before conversion, it lets you customize STL format (Binary or ASCII), Solid (single, per surface, or per physical surface), etc.

Do remember that before saving the output STL file, you need to manually enter the “.stl” file extension with the filename.

Additional Features:

  • It provides a Visibility feature which lets you view individual elementary entities, physical groups, and mesh partitions in different views like list, tree, numeric, etc.
  • You can also view statistics regarding a 3D model including geometry, mesh, and post-processing statistics.
  • It provides various inbuilt plugins which you can use when required.


It is another nice STEP to STL converter software which is very easy to use. You can also use it simply design mesh from scratch.

Autodesk 123D Design

Autodesk 123D Design is another STEP to STL converter software for Windows. It is a beautifully designed 2D and 3D CAD software which lets you create models in various 2D and 3D file formats, such as SVG, DXF, DWG, STL, STEP, X3D, etc. Using it, you can also view and edit existing models, and then convert them to another supported format. This way, you can easily convert a STEP model to STL format. Let’s check out a sorted procedure using which you can convert STP to STL.

How to convert STEP to STL in Autodesk 123D Design:

  • Click on the model icon present at the extreme left and go to Import > 3D Model option to browse and open a STEP file in this software.
  • Now, you can modify the 3D model present in STEP file using available tools like transform (rotate, smart rotate, align, scale, smart scale, etc.), insert objects like box, sphere, prism, cone, wedge, etc., sketch (rectangle, circle, polyline, arc, etc.), construct (extrude, revolve, sweep, loft), modify (press pull, split face, chamfer, shell, etc.), grouping, combine, text, etc.
  • Finally, convert the original or edited STEP model to STL by going to its model icon and clicking on Export as 3D > STL option. Prior to conversion, you can setup mesh tessellation settings (coarse, medium, or fine) and enable or disable output options including combine objects and export as ASCII.


It is free for non-commercial use only.


Autodesk 123D Design is a nice and hassle-free STEP to STL converter which can be used for a lot more other CAD utilities.

GOM Inspect

GOM Inspect is the next free STEP to STL converter software for Windows. It is basically a 3D model inspection software which lets you analyze 3D model files using a variety of tools. Using it, you can also convert an imported 3D model to another supported format which also includes conversion of STEP file to STL format. Apart from STL, it supports PLY, POL, G3D, and other output formats.

How to convert STEP to STL in GOM Inspect:

  • At first, click on its Import > File option from its File menu to open a STEP file. You can now view and analyze your 3D model with the help of various tools like rotate, zoom, standard views, isometric views, central projection, etc.
  • Secondly, go to the File menu and select Export > Mesh > STL option and set up some output options like data mode (Binary or ASCII), color, fie type, etc. After specifying output parameters, click on the Ok button to start the STEP to STL conversion.

Additional Features:

  • It provides a dedicated Construction menu using which you can draw various geometrical elements like circle, ellipse, cylinder, sphere, cone, surface, slotted hole, etc.
  • To analyze the 3D model and measuring data, you get tools like Check Dimensions, CAD Comparison, Check GD&T, heck Curves, Analyze Surface, Analyze Aerofoils, etc.
  • Besides exporting the model as mesh, you can save it as geometry in various formats like CSV, ASCII, IGES, UFF, etc.


GOM Inspect is a great 3D model analysis software which can also be used for STEP to STL conversion.


NuGraf is one more STEP to STL converter software for Windows. It can be used to simply import a STEP file and then convert it to STL format by using its export feature. Besides STEP to STL, other model conversions can be performed through it such as OBJ to 3DS, STL to DAE, OBJ to STL, STEP to OBJ, etc.

Along with simple conversion method (import and then export), it provides a “Batch Convert” Feature which lets you batch convert STEP to STL and other formats. Let’s see how.

How to convert STEP to STL in NuGraf:

Using NuGraf, you can convert STEP to STL in two ways, which are:

  1. In the first method, go to its File menu and click on Import 3D Geometry > “STEP” option to open a STEP file in it. You can now view the model using various views, move, rotate, zoom, and camera options. Finally, click on the File menu > Export 3D Geometry option and select “STL file” as the output format to initiate the conversion. Prior to conversion, you can set up some output options including line terminal type (CR/LF(DOS), LF (Unix), CR(Mac)), output only 1 solid entry, binary output (single solid), reverse orientation of triangles, and flip geometry normals.
  2. The second method is to use its Batch Convert option from the File menu. After clicking on this option, import one or more STEP files which you want to convert, set STL as export format, set up STL export options, and hit the Convert File button.


In this free version of NuGraf, every fifth polygon in each object is not converted in the output. You need to upgrade to its pro version to remove this limitation.


NuGraf is another alternative for you to convert STEP to STL. But, it has a major limitation as mentioned above. So, before opting this software, make sure the limitation has no impact on your output.

Related Posts
Write a Comment

Komal Srivastava

Technical Content Editor

About Us

Sample image

We are the team behind some of the most popular tech blogs, like: I LoveFree Software and Windows 8 Freeware.

More About Us