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Recurring Event Date Calculator

Enter a start date, interval and number of occurrences to list the dates.

How it is calculated

The first date is your start date (written as YYYY-MM-DD). The unit is days, weeks (7 days) or months, and the interval n is how many units apart the dates are. For days and weeks each date is the previous one plus the interval: datei+1 = datei + n × unit, which is exact and never drifts. For months every date is counted from the start date, start + k × n months, and if that month is too short the date is moved back to its last day: starting on January 31 with a 1-month interval gives January 31, February 28, March 31, April 30. The tool lists the requested dates, always including the start date as the first one, plus a count and the last date. If left blank, the interval is 1, the unit is weeks and the number of occurrences is 5. The interval and the number of occurrences must be whole numbers above zero, with at most 200 occurrences, and an unknown unit such as "years" shows no result.

Worked example

A meeting starts on 2025-03-03 and repeats every 2 weeks, 4 times. Two weeks is 14 days. Date 1 is 2025-03-03. Date 2: 03-03 + 14 days = 2025-03-17. Date 3: 03-17 + 14 days = 2025-03-31. Date 4: 03-31 + 14 days = 2025-04-14, because March has 31 days. The tool reports 4 dates and the last one is 2025-04-14, with the start date counting as the first occurrence.

Try this example →

Common mistakes

  • Typing the start date as 03/03/2025 or 3.3.2025. Only the exact YYYY-MM-DD form with a valid calendar date is accepted, and 2025-02-30 gives no result.
  • Expecting a monthly series from the 31st to hit the 31st every month. Short months are clamped to their last day, so the dates read 31 January, 28 February, 31 March, 30 April; check them if the exact day matters, such as a payment due date.
  • Choosing "months" when the event is every 4 weeks. Four weeks is 28 days, which drifts away from the calendar month; "every month" and "every 4 weeks" give different dates.
  • Forgetting that the start date counts as occurrence number 1. Asking for 4 occurrences gives the start plus three more, not four after the start.
  • Typing an interval of 0, a negative number or a decimal such as 1.5 weeks. None of these works, so the tool returns no result; use 10 days instead of 1.5 weeks.

About this calculator

This calculator generates a list of future dates from a start date and a repeating interval — every N days, every N weeks, or every N months — the same logic that underlies recurring events in calendar software and recurring billing cycles. Calendar apps store this pattern with a recurrence rule (the RRULE field defined in the iCalendar standard, RFC 5545), which encodes the frequency and interval so the app can expand it into individual occurrences on demand instead of storing every date.

People use this kind of date math to plan things like biweekly paychecks, monthly rent due dates, quarterly maintenance schedules, or every-other-Tuesday meetings — you enter a start date, the interval (in days, weeks, or months), and how many occurrences you want, and it lists each resulting date in order.

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