For sentences of 12 months and longer, federal inmates are permitted only a 15 percent sentence reduction for good behavior.
This is in accordance with the First Step Act of 2018. Vox reports that "Inmates who avoid a disciplinary record can currently get credits of up to 47 days per year incarcerated. The law increases the cap to 54, allowing well-behaved inmates to cut their prison sentences by an additional week for each year they’re incarcerated."
Other sources concur. The website for a group of federal defenders states, "For sentences of twelve months and one day or longer, a client is eligible for good time credit of up to 15 percent, as long as there have been no disciplinary problems."
A proposed Florida bill, Senate Bill 572, was set to reduce the non-violent crime serving requirement to 65 percent. However, in March 2020, this bill was "indefinitely postponed and withdrawn from consideration", according to the Florida Senate.