CDEG: Computerized Diagrammatic Euclidean Geometry


This is the home page for CDEG: Computerized Diagrammatic Euclidean Geometry, which impliments a formal system for giving diagrammatic proofs in planar geometry that are similar to the kinds of proofs Euclid gives in the Elements. The most recent version of CDEG is version 3.1 beta (released on May 30, 2017), and is recommended for most users. All versions of CDEG are distributed as zipped files which must be extracted to use. The program files are not signed, so you will most likely need to tell your computer to let them run anyway. In many cases you can do this by right-clicking on the application.

CDEG is free software, released under the terms of the Gnu Public License, version 3, as published by the Free Software Foundation.

You can download the most recent version, CDEG 3.1 beta, from the following links.  CDEG 3.1 is run through a graphical user interface, and is available in both Mac and Windows versions.  CDEG 3.1 is the version recommended for most users.  The zip files also include the CDEG 3.1 manual which explains how to use CDEG.  CDEG 3 is still under active development, and may be frequently updated.

The source files for CDEG 3.1 can be obtained by emailing me at

CDEG 2.0 is an older version that is referenced in some of my publications and is still available here.  CDEG 2.0 is run through a text-driven menu, and requires X11 to be already installed in order to run on Mac OS or Unix/linux systems.  X11 for mac can be downloaded and installed from the Xquartz project.  (CDEG 3.1 does not require X11.)

You can download CDEG 2.0 in the following forms:

Please let me know if you are using this program, and especially if you find any bugs! If you find bugs please send a transcript of the session in which the bug occurred to me at  Thanks for trying it out!

My other publications relating to CDEG can be downloaded from my research page.

Nathaniel Miller <>