AutoCAD 2009 with the Classic User Interface

In earlier releases, AutoCAD used primitive entities — such as lines, polylines, circles, arcs, and text — as the foundation for more complex objects. Since the mid-1990s, AutoCAD has supported custom objects through its C++ API. Modern AutoCAD includes a full set of basic solid modeling and 3D tools, but lacks some of the more advanced capabilities of solid modeling applications. With the release of AutoCAD 2007 came improved 3D modeling functionality. Which meant better navigation when working in 3D. Moreover it became more easy to edit 3D models. The mental ray engine was included in rendering, it was now possible to do quality renderings.

AutoCAD supports a number of application programming interfaces (APIs) for customization and automation. AutoCAD's native file format, DWG, and to a lesser extent, its interchange file format, DXF, have become de facto standards for CAD data interoperability. AutoCAD in recent years has included support for DWF, a format developed and promoted by Autodesk for publishing CAD data. In 2006, Autodesk estimated the number of active DWG files to be in excess of one billion. In the past, Autodesk has estimated the total number of DWG files in existence to be more than three billion.

AutoCAD currently runs exclusively on Microsoft desktop operating systems. Versions for Unix and Macintosh were released in the 1980s and 1990s, but these were later dropped. AutoCAD can run on an emulator or compatibility layer like VMware Workstation or Wine, albeit subject to various performance issues that can often arise when working with 3D objects or large drawings.

AutoCAD and AutoCAD LT are available for German, French, Italian, Spanish, Japanese, Korean, Chinese Simplified, Chinese Traditional, Russian, Czech, Polish, Hungarian, Brazilian Portuguese, Danish, Dutch, Swedish, Finnish, Norwegian and Vietnamese. The extent of localization varies from full translation of the product to documentation only.

AutoCAD LT is a "scaled down" version of AutoCAD. It costs less (approx. $1300.00 USD versus around $4,050 USD for the full AutoCAD). It is also available for purchase at computer stores, unlike AutoCAD which has to be purchased from an official Autodesk dealer. It was developed so Autodesk could have an entry-level CAD package available to compete in that price class. Today AutoCAD LT is marketed as a CAD package for those who only need 2D functionality. Compared to the full edition of AutoCAD, AutoCAD LT lacks several features. Most notably, it has no 3D modeling capabilities (though it has a full suite of 3D viewing functions for looking at 3D models created in other CAD packages) and does not include any programming interfaces, such as support for most 3rd party programs and does not support LISP programs. A full listing of differences is on the Autodesk website. AutoCAD LT originated by taking the codebase of AutoCAD and commenting out substantial portions, which allowed AutoCAD and AutoCAD LT to be developed simultaneously.

AutoCAD is licensed at a significant discount over commercial retail pricing to qualifying students and teachers, with both a 14 month and perpetual license available. The student version of AutoCAD is functionally identical to the full commercial version, with one exception: DWG files created or edited by a student version have an internal bit-flag set (the "educational flag"). When such a DWG file is printed by any version of AutoCAD (commercial or student), the output will include a plot stamp / banner on all four sides. Objects created in the Student Version cannot be used for commercial use. These Student Version objects can and will 'infect' a commercial version DWG file if imported.

The Autodesk student community provides registered students with free access to different Autodesk applications. While AutoCAD is not available as standalone downloadable application, students have access to some other applications, which include AutoCAD, such as Civil3D or AutoCAD Architecture.