Convert STEP
to IGES.

Updated 2026-10-19

To convert STEP (.step / .stp) to IGES (.iges / .igs), drop the file below and download the result, in the browser with nothing installed. An exact translation: nothing is tessellated in either direction.

2 solid-geometry conversions a day with no account. No card, no install.

No account needed
Drop a STEP file.step / .stp · up to 200 MB

On our servers. No account: deleted within 24 hours. Signed in: kept until you delete them. Never shared or used for training.

ResultExact

STEP and IGES both store B-rep geometry, so planes, cylinders, cones and NURBS survive and dimensions, radii and tangency are preserved exactly.

HowThree steps
  1. Drop your .step file above — up to 200 MB without an account.
  2. IGES is already selected as the output.
  3. Download the .iges. Without an account, files are deleted within 24 hours; signed in, they are kept until you delete them.
FormatsWhat you are holding

STEP file (ISO 10303) (.step / .stp)

STEP (ISO 10303) is the closest thing engineering has to a universal solid format. It stores exact B-rep geometry — a hole is a cylindrical face, not a ring of facets. Fusion 360, Inventor, Onshape, SOLIDWORKS, Creo, NX, CATIA and FreeCAD all read it; .step and .stp are the same format. AP242 supersedes AP203 and AP214.

What you send when the other side has to keep modelling, quote machining, or open the shape in a different CAD system.

IGES file (Initial Graphics Exchange Specification) (.iges / .igs)

IGES predates STEP and is still requested by older CAM systems and mould and die workflows. It stores exact geometry, but many IGES files are loose trimmed surfaces that never close into a watertight solid. Unless someone asks for IGES by name, STEP is the better choice.

A CAM programmer, toolmaker or legacy system asked for IGES, or you were handed one and need something current.

Questions7 answered
Is the STEP to IGES converter free?
Yes. 2 solid-geometry conversions a day with no account, of 5 in total. A free account converts 4 solid files a day and adds 25 credits. No card.
Will the IGES file keep exact curves and holes?
An exact translation: nothing is tessellated in either direction. STEP and IGES both store B-rep geometry, so planes, cylinders, cones and NURBS survive and dimensions, radii and tangency are preserved exactly.
Will the IGES file open in Fusion 360, Inventor or Onshape?
Yes. IGES is read directly by Fusion 360, Inventor, Onshape, SOLIDWORKS, Creo, NX and FreeCAD. It arrives as a solid body you can measure, mate and cut.
Should I use IGES or STEP?
STEP, unless a CAM system or toolmaker asks for IGES by name. Both carry exact geometry, but STEP is the current ISO standard and closes into a solid more reliably.
How big a file can I convert?
To a mesh format like STL: 300 MB with a free account, 200 MB without one. To STEP, Parasolid or SLDPRT: 140 MB, because rebuilding a solid takes about twice the memory of writing a mesh. Maker and Studio convert up to 830 MB and 380 MB — a large conversion on a paid plan gets the server to itself.
Is it safe to upload my STEP file?
Files travel encrypted and are processed by machine on our own servers — no third parties, no ads or trackers, no AI training.
Is my STEP file deleted after converting?
Without an account, the upload and the result are deleted within 24 hours. With an account, both stay in your files until you delete them; deleted files leave our servers within 24 hours.
Beyond convertingSame file, four workspaces

Keep the part open: fill it with a lattice, check it with FEA, texture a surface, or slice it into cut-ready sheets. These workspaces are in early access — create an account, then apply from inside the app.

Create free account See pricing

AlsoOther ways in
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Going the other way? Convert IGES to STEP.