If it is not posted online, you will have to call the facility and speak to the unit secretary or your inmate's counselor to get that information. Of course, your inmate knows their out-date, too.
https://www.inmateaid.com/ask-the-inmate/how-do-you-find-out-when-the-inmate-release-date-is#answer
Accepted Answer Date Created: June 19,2015