Updated 2026-10-17
To convert IGES to STL, drop the .iges or .igs file into the converter below and download the .stl. The exact surfaces are triangulated to within 0.02 mm, with edges sampled first so holes and chamfers keep their outline, and the STL is written in millimetres. 5 conversions a day are free with no account. If the IGES came from a CAD system you can ask, a STEP or an STL exported there is the cleaner source.
5 conversions a day with no account. No card, no install.
On our servers. No account: deleted within 24 hours. Signed in: kept until you delete them. Never shared or used for training.
Edges are sampled first, so chamfers, fillets and holes come through crisp. Default tolerance: 0.02 mm chord deviation, 0.1 rad angle — fine enough to print directly.
Tessellation is one-way — keep the IGES file if you will edit the shape later.
IGES holds exact geometry, trimmed surfaces described by equations. STL holds flat triangles. Every curved face becomes a fan of facets, no facet strays more than 0.02 mm from the true surface, and flat faces stay flat. Colours, levels and annotation are not carried.
The part worth knowing about is IGES itself. Many IGES files are a set of surfaces that sit edge to edge without ever having been joined into a solid, sometimes with small gaps between them. The conversion does not stitch them: each surface is triangulated where it is, so a gap in the IGES becomes an open edge in the STL. A slicer will flag such a mesh as not watertight, and some will refuse to print it.
The converter checks the IGES on the way in and says if it already had open shells or invalid faces, so you know the fault is in the source rather than in the conversion. For a print, the cure is upstream: a solid exported from the original model, as STEP or STL.
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.
STL is the lingua franca of 3D printing: a flat list of triangles. No unit, colour, material or history — a cylinder is a fan of flat strips. The missing unit is the classic cause of scale accidents. Every slicer and mesh tool reads it.
You are printing, meshing or sending to a bureau — where triangles are what is wanted.
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.
Going the other way? Convert STL to IGES.