Ansys Chemkin’s user preferences allow users to control certain settings in the behavior and operation of the Chemkin Interface. These include display options, default settings for units on variables and parameters, and customization of file extensions for input and output files. There are three ways to access the Preferences panel: using the Edit > Preferences option in the ribbon or the Menu bar, clicking the Preferences icon in the Icon bar(if the menu interface is enabled), or typing Ctrl-M. The Preferences panel consists of four tabs of settings, as described in the following sections.