By default, all software supports multiple file extensions. Gaussian supports at least 2 different file extensions. The basic files that Gaussian supports are .FCHK. However, not all of the extensions listed on the list are always used to save the effects of work in Gaussian. Very often, files with such extensions are used as source data files used by Gaussian.
Gaussian can be used to convert file formats between the file extensions listed below. You can open a file with one of the file extensions below via Gaussian and try to save it in another file format, also supported by Gaussian.