Take off a 1/4 of your sentence actually. For example if your biked 75 days, then you would get 25 days off. So if your sentence was 100 days, you would get off in 75.ultimateownage said:3 days of work takes off 1 day, and the shifts of three days add up to a whole day of work. So if you did it every day you were in jail, you would half your sentence.