Convert IGES or IGS to STEP online

Upload your .iges or .igs file to the converter at the top of this page and download one STEP file with the exact geometry in millimetres. FreeCAD, which is free, can also open an IGES and export STEP. Marathon OS is the paid route if you don't have CAD at hand: first 2 files free, then 1 credit per file.

First 2 files free, any size up to 300 MB. After that, 1 credit per file. Credit packs bring it down to $1.80 per file. Prices include tax, you pay only when you click Download and credits never expire.

Yes. .igs is the short extension for IGES and .stp for STEP; they convert the same way.

If the IGES holds B-rep solids (type 186), they're written as STEP solids. If it holds trimmed surfaces (type 144), the STEP holds the same surfaces: we don't sew them, so knit them in your CAD program. In a file where we rebuild a face whose trim STEP can't store, the faces are written as separate surfaces.

No. Curves and surfaces stay exact; nothing is meshed. What doesn't carry over is the information around the geometry: part names, colours, layers and any assembly structure.

Millimetres. We read the unit stored in the IGES, so an inch file comes out at the right size.

STEP is the current ISO standard for exchanging exact 3D models, and most CAD programs, suppliers and CAM tools read it. IGES is older, and many IGES files hold only surfaces. Converting gives you the same geometry in the format people ask for.

Yes. Every part comes across in its assembled position, as one model without part names or the assembly tree.

Yes. Every conversion comes with a free quality report with 11 checks, including a valid B-rep, the number of solids, a face count match with the IGES, a bounding-box match and whether surface types are preserved.

Yes. Our STEP to IGES conversion keeps the geometry exact. Closed solids can be written as IGES B-rep solids; otherwise you get trimmed surfaces.

IGES files from any CAD program, as .iges or .igs, up to 300 MB. We read both solids (type 186) and trimmed surfaces (type 144). Files that use commas as decimal points, which some SolidWorks setups write, are fixed before reading.

To upload your own file, sign in with Google or an emailed code. The sample file works without signing in.

It depends on the file. Large assemblies can take several minutes, and we email you when the file is ready.

Uploads and downloads use HTTPS. Uploaded and converted files are deleted automatically after 7 days, and converted files aren't added to the public CAD library unless you publish them. You keep ownership of your design. See the Privacy Policy.