Welcome to DotWhat? ... The leading file extension resource

Thanks to years of research and help from our loyal visitors, we now have one of the world's largest and most detailed databases of file extension information, covering multiple operating systems from Microsoft's Windows, Apple's OS X and all variations of Unix to those used on the latest mobile devices and phones.

Everything you need to know! If not, just ask!

We try to provide as much information on each file extension as possible and we encourage visitors to contact us if they have any additional information on an extension or if they think a new file extension should be added to the database. Alternatively, each entry can be edited and visitors have the option of adding a comment, question or tip!