Code of Civil Procedure CCP § 12c

(a) Where any law requires an act to be performed no later than a specified number of days before a hearing date, the last day to perform that act shall be determined by counting backward from the hearing date, excluding the day of the hearing as provided by Section 12 .

(b) Any additional days added to the specified number of days because of a particular method of service shall be computed by counting backward from the day determined in accordance with subdivision (a).