3dfileconverter.onlineSTEP to STL Converter
Convert STEP or STP files to STL in your browser. Choose mesh precision, preview CAD geometry and export a triangle mesh without uploading your model files.
Enable JavaScript to open a model and use the interactive workspace.
How do I use this tool?
- Choose a STEP file from your device.
- Preview your model and adjust the settings.
- Create your output and download the result.
What does this tool do?
A finer mesh follows curves more closely, but requires more memory and produces larger files. STL does not retain materials or explicit units.
What are the file limits?
Models are processed locally. Inputs are limited to 50 MB per file and 500,000 triangles after import. Individual operations may have lower limits described below. Performance depends on your device.
JavaScript, WebAssembly and WebGL are required for the interactive workspace.
How are models processed?
Mesh loading and rendering use Three.js. STEP import and tessellation use occt-import-js, based on Open Cascade. These sources describe the underlying libraries; this tool's supported features and limits are listed on this page.
Frequently asked questions
How do I convert a STEP file for a 3D printing slicer?
Choose a tessellation precision, open the STEP or STP file and inspect the mesh. Select your output unit and export STL. Confirm the scale and printing settings in your slicer; file conversion is not a printability check.
Why do curved surfaces look faceted in STL?
STL approximates curves with triangles. Fine precision produces a closer approximation at the cost of more triangles and memory. Reload the STEP file after changing precision. The imported mesh must stay within 500,000 triangles.
Should I choose binary or ASCII STL?
Both encodings describe triangle geometry. Binary STL is normally smaller. ASCII STL is readable as text and may be useful when another application explicitly requires it. Neither encoding retains CAD features or materials.
Can I export a STEP assembly as separate STL files?
This conversion page exports the selected geometry into one STL file while retaining its placement. To download one file per imported mesh part, use Export parts and select the parts you need. STL does not preserve assembly constraints or reliable part names.