Never miss a deadline.

Which tool answers your question

Both calculators on this site do date math, but they answer different questions, and picking the wrong one is how people miscount a deadline without noticing. If you have a trigger date, like the date a complaint was served or an order was entered, and a rule that says how many days you get, use the Deadline Calculator. Feed it the start date, the day count, and whether the rule counts calendar days or court days, and it returns the exact date the clock runs out. If instead you already have two dates, say a scheduling order that spans June 1 to June 30, and you need to know how many working days that actually covers, use the Business Days Calculator. It counts inclusively from the first date through the second and reports business days, weekend days, and federal holidays separately, which matters when a filing letter cites "20 business days" and you need to check the math yourself.

A third page, the 2026 Civil Litigation Deadline Reference, is not a calculator at all. It is the source table: the answer, discovery-response, and appeal windows both tools are built on, with the FRCP and FRAP rule citations attached to each one, plus a CSV if you want the numbers outside a browser. Start there if you are not sure how many days a rule actually gives you before you run the calculator. If your matter is a California claim, note that the state runs its own set of periods entirely separate from the federal defaults above; see the breakdown of California's deadlines by claim type for the injury, contract, and government-claim numbers.

What the calculators assume, and where that stops being true

Both tools exclude Saturdays, Sundays, and the eleven U.S. federal holidays recognized under FRCP Rule 6(a)(6): New Year's Day, Martin Luther King Jr.'s Birthday, Washington's Birthday, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day, and Christmas Day. That list is federal. State courts routinely close for additional days, county holidays, or a court-specific administrative closure that a federal calendar has never heard of, and neither calculator on this site can see those. The Deadline Calculator also follows FRCP Rule 6(a)(1)(A): the triggering day itself does not count, and counting starts the next day. Some state rules count the trigger day, or count differently near the end of a period, which is exactly the kind of local variation these tools cannot verify for every jurisdiction. Treat both calculators as a fast first pass built on federal defaults, not a substitute for reading the rule that actually governs your filing.

Where a day gets lost

The single most common mistake is assuming "days" always means calendar days. A rule that says "20 days" without qualification is usually calendar days under FRCP Rule 6(a)(1)(C), while a rule that specifies "court days" or "business days" skips weekends and holidays, and those two counts can land more than a week apart on the same trigger date. The second mistake is forgetting the weekend-and-holiday extension: if the last day of a period falls on a Saturday, Sunday, or legal holiday, the deadline rolls forward to the next day that is not one of those, under Rule 6(a)(1)(C), so the filed-by date is not always the date you get from raw subtraction. The third is trusting a federal holiday list for a state court matter. State courts publish their own closure calendars, and a county holiday that never touches the federal list can still move a filing deadline. When a deadline actually matters, run it through the calculator for a fast answer, then check that answer against the rule text and the specific court's calendar before you rely on it.