Rule 4 Calculation of Time Limits

[Periods Expressed in Years] Any period expressed in years shall expire, in the relevant subsequent year, in the month having the same name and on the day having the same number as the month and the day of the event from which the period starts to run, except that, where the event occurred on February 29 and in the relevant subsequent year February ends on the 28th, the period shall expire on February 28.

[Periods Expressed in Months] Any period expressed in months shall expire, in the relevant subsequent month, on the day which has the same number as the day of the event from which the period starts to run, except that, where the relevant subsequent month has no day with the same number, the period shall expire on the last day of that month.

[Periods Expressed in Days] The calculation of any period expressed in days shall start with the day following the day on which the relevant event occurred and shall expire accordingly.

[Expiry on a Day on Which the International Bureau or an Office Is Not Open to the Public] If a period expires on a day on which the International Bureau or the Office concerned is not open to the public, the period shall, notwithstanding paragraphs (1) to (3), expire on the first subsequent day on which the International Bureau or the Office concerned is open to the public.

[Indication of the Date of Expiry] The International Bureau shall, in all cases in which it communicates a time limit, indicate the date of the expiry, according to paragraphs (1) to (3), of the said time limit.