CAD & 3D • MIME: application/step

.STEP File Extension

Universal 3D CAD exchange format for solid model geometry and assembly structure.

Category CAD & 3D
MIME Type application/step
Magic Bytes 23 49 53 4F 2D 31 30 33 30 33 2D 32 31 (#ISO-10303-21)
Developer ISO Technical Committee TC 184
Typical Size 5 MB – 180 MB
Security Risk Low Risk

Format Architecture & Technical Specifications

STEP (Standard for the Exchange of Product Model Data, ISO 10303) is a neutral 3D CAD exchange file format designed to facilitate interoperability between different mechanical CAD systems like SolidWorks, CATIA, Inventor, and Creo.

How to Open .STEP Files

1 Open in FreeCAD

Launch FreeCAD and select File > Import > .step file.

2 View in eDrawings

Double click .step file in eDrawings Viewer to inspect 3D assemblies and cross sections.

Compatible Software Programs

FreeCAD Parametric Modeler

windows, mac, linux • Free

Autodesk Fusion 360

windows, mac • Free

SolidWorks

windows • Commercial

eDrawings Viewer

windows, mac • Free

Security Considerations & Verification

Text-based CAD boundary representation geometry format. Safe.

  • Open STEP file in text editor to confirm HEADER; and END-ISO-10303-21; delimiter blocks exist.

Frequently Asked Questions

What is a .STEP file?

A .STEP file is a ISO 10303 STEP CAD Model associated with CAD & 3D. Universal 3D CAD exchange format for solid model geometry and assembly structure.

How do I open a .STEP file on Windows or Mac?

You can open .STEP files using FreeCAD Parametric Modeler, Autodesk Fusion 360, SolidWorks, eDrawings Viewer. If you do not have native software installed, you can use AnyFileX's free File Identifier or convert .STEP to a standard format in your browser.

Is a .STEP file safe to open?

This format carries a safety rating of Low Risk. Text-based CAD boundary representation geometry format. Safe.

Can I convert a .STEP file to other formats?

Yes! .STEP can be converted to formats such as .STL, .OBJ directly in your web browser.

What should I do if a .STEP file is corrupted or won't open?

If your .STEP file displays an invalid header or signature error, check its magic bytes hex header (23 49 53 4F 2D 31 30 33 30 33 2D 32 31 (#ISO-10303-21)) using AnyFileX's Magic Byte Detector or follow our step-by-step file repair guide.