The appellants, four inmates of the Kettle Moraine Correctional Institution, claim that their mandatory release dates were improperly calculated. They assert that their release dates were calculated on a straight 360-day year rather than the true 365-day year (with the 366-day leap year) known as the Gregorian calendar. They conclude that the calculation extends their sentences beyond that set by the courts and are therefore unconstitutional. They demand immediate release.

Their claim, and consequently this appeal, is meritless. As succinctly noted by the trial court, using a standard 360-day year calendar rather than the Gregorian calendar simplifies sentence computation. Each month is treated as a 30-day month. The effect of this is to benefit every inmate by awarding credit for an extra five days per year. So, rather than extending the sentence, the use of the 360-day calendar actually shortens the time. The calendar inures to every inmate’s benefit. Therefore, there is no unconstitutional extension of lost liberty.1 We affirm.

By the Court. — Orders affirmed.