3dfileconverter.onlineBatch STEP to STL Converter
Batch convert STEP and STP files to STL locally in your browser. Queue up to 10 files, review individual failures and download successful outputs in a ZIP.
Enable JavaScript to open a model and use the interactive workspace.
How do I use this tool?
- Choose an OBJ, STL or STEP model from your device.
- Choose one output format for the queue.
- Create your output and download the result.
What does this tool do?
Files are processed one at a time. Up to 10 files, 50 MB per file and 150 MB total. Each output uses the same format, unit and precision settings. Failed files are reported separately; successful outputs can still be downloaded.
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
Which 3D files can I batch convert?
Add OBJ, STL, STEP or STP files to the queue and choose one output format: OBJ, STL, GLB or faceted STEP. All files use the same selected unit and precision settings. Faceted STEP export has its own 20,000-triangle and topology restrictions.
How many files can I process at once?
A queue can contain up to 10 files, with a 50 MB limit per file and 150 MB total input. Files are processed one at a time. The accumulated uncompressed output is limited to 200 MB.
What happens if one file cannot be converted?
The queue reports that file as failed and keeps successful results available. The downloaded ZIP contains successful outputs and a failure report when files have failed, so you can review and retry those inputs separately.
Can I mix files that use different source units?
The queue uses one common unit setting for OBJ and STL inputs, so group files with the same source unit together. STEP carries its own units and is imported in millimeters. Separate batches are safer when the unit conventions differ.