A perpetual calendar which has transparent letters and numbers positioned in a predetermined matrix arrangement on an opaque sheet. Within the predetermined matrix arrangement of numbers and letters are abbreviations for the name of each day of the week, each month of the year, and the numerals one through thirty-one. Small pieces of opaque material which will adhere to the sheet are sized to overlie any abbreviation of the name of the days of the week, any abbreviation for the months of the year, and any numerals between one and thirty-one within the matrix so that any calendar date can be readily indicated on the calendar by adhering the pieces of opaque material to the rear of the transparent letters and numerals within the matrix defining the particular month and name of day abbreviations and the day of the month.