The triggering day is excluded
Texas Rule of Civil Procedure 4 explains how to compute a period prescribed or allowed by the rules, a court order or an applicable statute. Exclude the day of the act, event or default that starts the period. Include the last day, unless it falls on a Saturday, Sunday or legal holiday; in that event, the period runs through the next day that is none of those.
Short periods have a separate counting rule
For periods of five days or less in these rules, do not count Saturdays, Sundays or legal holidays. Rule 4 expressly excepts the three-day mail extensions referenced in Rules 21 and 21a: those days count for that extension.
Identify the deadline before counting
First identify the rule or order that supplies the period and the event that starts it. A response period after service and a period after a judgment is signed can begin from different events. Use the illustration to review the counting method, then read the provision governing the particular deadline.
The illustrated guide
Starting day, last day, short periods and the mail-extension exception.