How many monts is one year in jail

One year in jail equals 12 months. However, every jail calculates something they call "good-time credits" which usually ends up shaving a certain number of days off per month served. This varies from one county jail to the next. However, by way of an example here in the county where I live and work the county jail calculates good-time at a rate of 5 days for every 30 days served; therefore, a 12 month sentence would accumulate 5 days every month. Five days multiplied by 12 equals 60 which would mean that a 12 month sentence would mean that a person would actually serve 10 months. However, like I stated earlier, this varies from county to county and state to state.