Abstract: The specification discloses a perpetual monthly calendar in which numbered belts are adjustable to bring the numbers of a year to a year window, a month belt is adjustable to bring the month (with the number of days therein) to a month window, a day belt having six horizontal rows of numbers adjustable to bring the appropriate monthly calendar to a day window with the first of the month under the day of the week on which the month of a row of the days of the week is above the day window and exposing consecutive day numbers of that month in the day window. A sixth row pointer is adjustably positioned just beyond the last day of the month exposed when next day is in the sixth row. A fifth row pointer is adjustably positioned beyond the last day of the month exposed when the next day is in the fifth row.