Convert STEP to STL
Convert a STEP file to STL in your browser. Free, no upload, no sign-up.
Convert STEP files to STL directly in your browser. The converter reads the exact STEP geometry with the OpenCascade CAD kernel running in WebAssembly, tessellates it at the quality you choose and writes a STL file. Nothing is uploaded, there is no file size limit beyond your computer's memory, and the result downloads instantly. STL is accepted by every slicer and 3D printer, so it is the safest format to hand to anyone who needs to print your model.
How to convert STEP to STL
- 1Drop your STEP file
Drag a .step file onto the box above or click to choose one. The exact geometry is tessellated into triangles in your browser using OpenCascade (the same kernel FreeCAD uses). You can control the mesh density before exporting. Large assemblies may take a while; the first load downloads a 7 MB engine.
- 2Pick the mesh quality
Fine gives smoother curves and a larger file, coarse keeps large assemblies light. The default suits most 3D printing jobs.
- 3Check the preview
The model renders in 3D so you can confirm it loaded correctly. Dimensions, volume and triangle count are shown next to it; open edges are flagged if the mesh is not watertight.
- 4Download the STL
Adjust the export options if needed and click download. Colors, textures and materials are dropped because STL cannot store them. Multiple objects are merged into one triangle soup; units are not recorded, so make sure the model is already in millimeters.
What is a STEP file?
STEP (ISO 10303, files ending in .step or .stp) is the neutral CAD exchange format. Unlike mesh formats it stores exact B-rep geometry: analytic surfaces, NURBS, edges and assembly structure with real units. Every CAD system can export STEP, and it is what you receive from suppliers, McMaster-Carr or GrabCAD.
Commonly used by: SolidWorks, Fusion 360, Onshape, FreeCAD, CATIA, Siemens NX, machine shops
The exact geometry is tessellated into triangles in your browser using OpenCascade (the same kernel FreeCAD uses). You can control the mesh density before exporting. Large assemblies may take a while; the first load downloads a 7 MB engine.
What is a STL file?
STL is the oldest and most widely supported 3D printing format. It stores nothing but a list of triangles, with no color, texture, unit or scale information. Every slicer and almost every 3D tool can read it, which is why it is still the default exchange format for printable models.
Commonly used by: 3D printer slicers (Cura, PrusaSlicer, Bambu Studio), CAD export, Thingiverse / Printables
STL is accepted by every slicer and 3D printer, so it is the safest format to hand to anyone who needs to print your model.
STEP vs STL
| STEP | STL | |
|---|---|---|
| Full name | Standard for the Exchange of Product Data (ISO 10303) | Stereolithography |
| Encoding | Text | Text or binary |
| Geometry type | Exact (B-rep / curves) | Triangle mesh |
| Colors | Yes | No |
| Textures | No | No |
| Materials | No | No |
| Stores units | Yes | No |
| Multiple objects | Yes | No |
| Typical use | SolidWorks, Fusion 360, Onshape | 3D printer slicers (Cura, PrusaSlicer, Bambu Studio), CAD export, Thingiverse / Printables |