They will serve 85% of their time unless this is a county jail and the overcrowding is critical. Some inmates with short sentences that are related to non-violent offenses might get out a bit earlier to make room.
https://www.inmateaid.com/ask-the-inmate/if-someone-gets-sentenced-to-60-days-in-jail-could-they-get-out-early#answer
Accepted Answer Date Created: February 27,2016