Free online STEP to IGES converter

Convert STEP to IGES with CAD software or 101convert.com, and check geometry after export.

Convert STEP to IGES online - free

.step .iges

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How to convert step to iges file

July 1, 2026
CAD formats
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Source format: STEP

STEP is a widely used 3D CAD exchange format defined by the ISO standard, commonly saved as .step or .stp. It is used to transfer solid models, assemblies, and product data between CAD systems. STEP is popular because it usually preserves geometry and, in many cases, assembly structure and metadata better than older exchange formats.

Target format: IGES

IGES stands for Initial Graphics Exchange Specification and is a long-established CAD interchange format, usually using .igs or .iges. It is often used for exchanging surface geometry, wireframes, and some solids between CAD applications. IGES is still supported by many engineering tools, especially in legacy workflows, but it is generally less capable than STEP for modern product data exchange.

How to convert STEP to IGES

The most reliable method is to use a CAD program that can open STEP files and export IGES. If your software supports both formats, the conversion is usually straightforward.

Open the STEP file in your CAD software.
Verify that the model imports correctly and that the units are correct.
Choose File → Save As or File → Export.
Select IGES as the output format.
Adjust export options if available, such as units, surface or solid export, and tolerance.
Save the file with an .igs or .iges extension.

Common desktop tools that can do this include FreeCAD, SolidWorks, Autodesk Inventor, Fusion 360, CATIA, Siemens NX, and PTC Creo, depending on your license and installed translators. If you do not want to install software, you can convert the file on 101convert.com for free.

In FreeCAD, for example, you can open the STEP file and then use File → Export and choose IGES if the IGES exporter is available in your build. In many CAD systems, the export dialog lets you choose whether to write surfaces only or attempt to preserve solids as IGES entities.

Quality and compatibility notes

STEP to IGES is often a downgrade in exchange fidelity. STEP usually preserves modern CAD data more reliably, while IGES may lose or simplify some information during export. This is especially important for assemblies, colors, feature history, constraints, and metadata, which IGES typically does not handle well.

Geometry may also change slightly because different CAD systems use different tolerances and entity types. After conversion, inspect the IGES file in the target CAD program to confirm that faces, edges, and units imported correctly. If the goal is manufacturing or collaboration with modern CAD systems, STEP is usually the better target; use IGES mainly when a downstream system specifically requires it.

STEP vs IGES: format comparison

How the STEP and IGES formats compare on the properties that matter most for this conversion.

Comparison of the STEP and IGES file formats
Property	.STEP Standard for the Exchange of Product model data	.IGES Initial Graphics Exchange Specification
Dimensions	3D	3D
Geometry	Both	Both
Materials	Yes	—
Plain-text readable	Yes	Yes
Operating system support	Wide	Wide
Typical file size	Medium	Large
Open standard	Yes	Partly open
Introduced	1994	1980
Developer	ISO	IGES/PDES Organization; later maintained through ANSI/ASME standardization
MIME type	application/step	—

Open STEP file Open IGES file

Frequently asked questions

Is the STEP to IGES converter free?

Yes, converting STEP to IGES on 101convert.com is completely free. No registration, email address or installation is required. If you need a higher file size limit or want to convert more files at once, see our plans.

How large can my STEP file be?

You can upload STEP files up to 500 MB and convert up to 5 files at once in a single batch.

What happens to my uploaded files?

Files are processed automatically and deleted from our servers within a few minutes after conversion. We never view or share your files.

Do I need to install any software to convert STEP to IGES?

No. The STEP to IGES conversion runs entirely online in your browser and works on Windows, Mac, Linux, Android and iPhone.

Did the conversion fail?

In most cases, the cause is an incorrect file format. Please upload a valid STEP file for this STEP to IGES conversion. Occasionally, the issue may be on our side. We analyze recurring conversion failures and disable or fix the converter if we detect a defect.

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Free online STEP to IGES converter