DXF versions: R12 to 2018

DXF versions follow AutoCAD releases, from R12 (AC1009) to 2018 (AC1032), and each newer version adds entity types that older software cannot read. Every version comes in ASCII and binary form. The viewer on this site opens both forms in any version, so you can check what a file contains before sending it on.

DXF version table

Releases between these, such as 2011 or 2021, write the same format as the version above them in the table. That is why a "2021 DXF" reports AC1032.

How to tell which version a DXF file is

Open an ASCII DXF in a text editor and search for $ACADVER. The line below the next 1 holds the code, for example AC1015 for a 2000 file. The header sits at the start of the file, so you do not need to scroll far.

A file that starts with the words "AutoCAD Binary DXF" is binary, and a text editor shows mostly unreadable characters. Open it in a CAD program or drop it on the viewer here, and check the version in the file properties.

Files exported by laser, CNC, and drawing programs sometimes have no header at all. Such headerless files behave like R12 and open almost everywhere.

ASCII vs binary DXF

ASCII DXF writes every value as text: a group code on one line, its value on the next. Anyone can read it, scripts can generate it, and it compresses well in ZIP. The cost is size and speed; a large site plan can reach hundreds of megabytes.

Binary DXF stores the same groups as raw numbers. Files are about a quarter smaller and load faster, and the numbers keep their full precision. Many programs outside the CAD world, including some cutting software, read only ASCII, so binary is mostly used between CAD programs. When in doubt, choose ASCII.

Why shops still ask for R12 DXF

Laser, plasma, waterjet, and CNC software often implements only the R12 entity set. An R12 file has no LWPOLYLINE, no SPLINE, and no ELLIPSE: curves come out as arcs, polylines, or short line segments, which every machine controller understands. A newer DXF with splines may open with missing curves or not at all.

The trade-offs are real. Splines become many segments, true colors drop to the 255 indexed colors, and non-English text may lose characters because R12 relies on a code page instead of UTF-8. For drawings exchanged between modern CAD programs, use 2007 or newer; for cutting, ask the shop and default to R12.

Colors, layers, text, and scale in DXF

• Color. Each entity uses an AutoCAD Color Index from 1 to 255 or "by layer". From 2004 on, a 24-bit true color can be stored as well.
• Layers. Every entity names its layer; layer color, linetype, and visibility live in the table section near the top of the file.
• Text and fonts. A text style names a font file, SHX or TrueType, but the font itself is never inside the DXF. Without the font, programs substitute another.
• Scale. DXF coordinates have no fixed unit. The $INSUNITS header can declare millimeters or inches, but many programs ignore or omit it, so measure a known distance after import.

The viewer here shows layers with their colors, substitutes missing fonts, and lets you measure in drawing units. Drop a file on dwgviewer.app to check it; nothing is uploaded. The DWG side of the same story is on DWG versions, and the format basics on what is a DXF file. To change a file's version, open it in a CAD program and save it again, or see how to open a DXF file for programs that can.

Frequently asked questions