A .dat file extension is generally used for storing Data. DAT file extension are meant to store any type of data, i.e. text, media, graphics, or binary data. A .DAT file format has no predefined structure of its own. A standard text editor can be used for opening and reading a DAT file to determine its relation with an application via the content it's storing. Generally, a DAT file is associated with a program's functioning, i.e. is responsible for telling a program what to do and what not to.