The invention relates to a calendar corrector for arrangement in a movement of a watchmaking part provided with calendar display means (12) and a thirty-one wheel (10) which goes round in thirty-one days. Said corrector comprises manual control means (18,19), enabling information relating to the fact that the current month comprises less than thirty-one days, to be introduced and programming means (14,15,16,17, 22, 25) coupled to the thirty-one wheel (10), responding to the information introduced by the control means such that the display means can be corrected automatically at the end of said current month.