What is a DXF file?

By Tiago Almeida · Updated 30 October 2026

A DXF file is a drawing saved in a form that almost any design program can read. CAD apps export it, and laser cutters, CNC routers, plasma tables and vinyl cutters import it, so it's usually the file people send when they want a part made.

DWG Viewer, our Mac app, opens DXF files, so weigh that in where it comes up. Everything else here applies whatever you open them with.

Where DXF comes from

Autodesk introduced DXF with the first version of AutoCAD in December 1982. AutoCAD keeps its own drawings in DWG, a compact binary format whose specification Autodesk has never published, so DXF was how a drawing got out to other programs. Autodesk calls it the drawing interchange format, though you'll often see it called drawing exchange format.

Unlike DWG, DXF is documented. Autodesk still publishes the DXF reference for every AutoCAD release, up to AutoCAD 2027, and that's why software from almost any field can read it.

What's inside a DXF file

Most DXF files are plain text, and if you open one in TextEdit you'll see a long column of pairs. Each pair is a number, called a group code, followed by a value, and the code says what the value means: 0 starts a new object, 8 gives its layer, and 10, 20 and 30 are the X, Y and Z of its first point. Here's a line 120 units long on a layer called CUT, as an R12 DXF stores it:

The file is split into sections. The header holds the drawing's settings, and the tables list its layers, linetypes and text styles. The blocks section holds reusable parts, such as a bolt or a door, and the entities section holds what you actually see: lines, arcs, circles, polylines, splines, text, hatches and dimensions. A DXF can also be saved in binary, which Autodesk says is much smaller and faster to read, but you'll rarely be sent one.

Why laser and CNC software asks for DXF

A DXF holds exact geometry. A circle is stored as a centre and a radius, not as a ring of pixels, so it stays a perfect circle at any size, and that's what a machine needs to follow. Each object also carries a layer name and a colour, which laser and CNC programs use to tell cuts from engraving, or pockets from profiles.

Most programs that drive a machine import DXF, and so do cutting services: SendCutSend builds its instant quotes from DXF, AI and EPS files. A few prefer other formats. Glowforge, for example, takes SVG and PDF, and DXF only from Premium members. There's more on that choice in SVG or DXF for laser cutting and CNC?

Why a part comes in at the wrong size

The numbers in a DXF have no units attached, so a line 120 long could be 120 millimetres or 120 inches. The header has a setting called $INSUNITS that can say which, but many files leave it unset, and AutoCAD itself uses it for scaling blocks rather than the drawing. So most laser and CNC programs ask you for the units, or assume them.

Get it wrong and a part drawn in inches comes in 25.4 times too small, or a millimetre part 25.4 times too big. LightBurn's import settings warn about exactly this. After importing, measure one dimension you know, and if it's off, ask the sender which units they drew in.

DXF versions

AutoCAD saves DXF in the version that matches its DWG format, so you'll see DXF files called R12, 2000, 2004, 2007, 2010, 2013 and 2018. Each version added things that older software may not understand, such as splines and ellipses stored as true curves.

If a program refuses a DXF, or parts of it go missing, saving it again as an older version often fixes it. R12 is the oldest and simplest. It can't hold splines or ellipses, so they're turned into many short straight segments, and multi-line text and hatches are broken into simpler pieces. That's usually fine for cutting, which is why many laser and CNC users ask for R12.

Common reasons a DXF won't cut properly

It's the wrong size. The units were missed or guessed, as described above.
The text is missing or in the wrong font. A DXF stores text as letters and a font name rather than shapes, so the cutting program needs the same font, and many skip text altogether. Convert text to outlines before you send the file.
A shape won't cut as one piece. Its outline is made of separate lines that don't quite meet, so the software can't see a closed shape. Join them into one polyline.
Some lines cut twice. Duplicate lines sit on top of each other, which often happens when drawings are copied together. AutoCAD's OVERKILL command removes them, and most CAD apps have something similar.
A 3D part shows nothing. A DXF stores 3D solids as data that most cutting programs can't read. Export a flat 2D view of the part instead.

DXF or DWG?

DWG is AutoCAD's own format, and DXF is the one meant for sharing. Both can hold the same drawing, but DWG is compact, binary and undocumented, so laser and CNC software almost always asks for DXF. If you've been sent a DWG, What is a DWG file? explains it, and DWG Viewer can save it as a DXF.

How to open a DXF file on a Mac

macOS can't open DXF files by itself. DWG Viewer, our app, opens them with Finder thumbnails, a space-bar preview, layers and measuring in the drawing's own units, and exports them to PDF and SVG. It costs $19 once and doesn't edit drawings. For free, LibreCAD and QCAD edit DXF files, and Inkscape imports them for turning into SVG. How to open .dxf files on a Mac compares every option.

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DWG Viewer is not made by or affiliated with Autodesk, Inc. Autodesk, AutoCAD, DWG, DXF, DWF, Revit and Inventor are trademarks of Autodesk, Inc.