Dates and deadlines, counted where you can see the rule

The live calculator is at /date-calculator/. This page explains the method.

Worked example: notice served Friday 6 March 2026. Thirty calendar days exclusive of the day of service. Day 1 is 7 March. Day 30 is Sunday 5 April 2026. A next-business-day rule would roll to Monday 6 April. Those are different clocks.

• Days between two dates — Inclusive and exclusive calendar spans — the off-by-one most people actually mean.
• Business days — Monday–Friday counts, with an optional U.S. holiday skip you can see.
• Add or subtract days — Move a start date forward or back by calendar days.
• Time zone converter — A date and time between zones you name — not a silent local clock.
• 1031 exchange deadlines — 45-day identification and 180-day exchange clocks from closing.
• Landlord / tenant notices — 3-day through 90-day counting pages. You type the period on the notice; we do not look up your county.

FAQ

Does the date calculator know my state’s notice statute?

No. You enter the period that is already on the notice or the contract. A 3-day URL is a counting page, not a claim that every county uses three days. Confirm the primary source when the date matters.

Why isn’t this one giant “date widget”?

A 1031 exchange runs 45 and 180 calendar days from closing at the same time. A lease notice may run backward from term-end. A discovery response may add mail days. Those are different conventions. Separate pages keep the rule on the screen.

Is this legal or tax advice?

No. It is educational calendar math with the counting method written out. Read the disclaimer on the calculator. Confirm with counsel or the agency when a deadline has consequences.