Federal Rule of Civil Procedure 6 governs how to count time. Get it wrong and you miss a filing deadline by one day. Here is the rule, the mechanics, and the gotchas.

The basic rule (FRCP 6(a)(1))

When the period is stated in days or longer:

Exclude the day of the event that triggers the period.
Count every day, including weekends and legal holidays.
Include the last day. If the last day is a Saturday, Sunday, or legal holiday, the period continues to the next day that is not.

Periods stated in hours (FRCP 6(a)(2))

Begin counting immediately on the occurrence of the event. Count every hour, including hours during weekends and legal holidays. If the period ends on a weekend or holiday, the period continues to the same time on the next day that is not.

"Legal holiday" defined (FRCP 6(a)(6))

A legal holiday is:

New Year's Day, Martin Luther King Jr. Day, Washington's Birthday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day, Christmas Day; and
Any day declared a holiday by the President or Congress; and
For periods that end at the close of business of the clerk's office, any day declared a holiday by the state where the district court is located.

Computing from service vs filing

A 21-day window to respond to a complaint runs from the date of service, not the date of filing. Note that mail service adds 3 days under FRCP 6(d).

Worked examples

Example 1. Complaint served Monday, June 1. 21 days to answer. Excluding June 1, day 1 is June 2; day 21 is June 22. June 22 is a Monday. Answer due June 22.

Example 2. Same service. But Day 21 (June 22) is the federal Juneteenth holiday in 2026. The period continues to the next non-weekend, non-holiday: June 23. Answer due June 23.

Example 3. Motion to dismiss filed Friday, July 31. Plaintiff has 21 days to oppose. Day 1 is August 1; day 21 is August 21. August 21 is a Friday — not a holiday, not a weekend. Opposition due August 21.

State-court variations

State rules vary. California excludes weekends for periods of 11 days or less (CCP § 12a). New York has its own quirks. Always check the state rule when computing in state court.

How Draftiro handles it

Draftiro computes federal deadlines under FRCP 6 with the current legal-holiday list and surfaces the cited rule on the deadline view. For the five states whose rules we model — California, New York, Texas, Florida, and Illinois — state-court deadlines are computed under the applicable state rule; elsewhere Draftiro shows the federal calculation and prompts you to confirm the state rule by hand. The calculated date is annotated with the rule, so a paralegal or co-counsel can verify the math.

Related reading: the FRCP Rule 6 and legal holiday glossary entries, the deeper federal vs state court-day math explainer, and the California and New York state pages.