How are good time credits calculated on prison sentences?

For federal sentences, the date posted on the federal website bop.gov is the release date of record. This date includes the 15% good time credit that is factored in on the day you arrive. The only change to this date happens if you do something unwise (incident reports requiring punishment) where they take days or weeks away from this privilege, OR you have completed the RDAP program, which will affect the out date by up to 12 months OFF the sentence. RDAP gets deducted at a later date when you are approved for the program and are scheduled for enrollment into a class number.