RRULE Builder
Build RFC 5545 compliant RRULE (recurrence rule) strings with a visual GUI, preview dates, and export as ICS files
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How to Use
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- 1
Select Frequency
Choose a recurrence frequency: daily, weekly, monthly, or yearly
- 2
Configure Details
Set the interval, days, dates, and end conditions
- 3
Review & Export
Copy the generated RRULE string or download as an ICS file
Builder
RRULE Output
Date Preview
Next occurrences (10 occurrences)
- 1.Mon, April 20, 20262026-04-20
- 2.Mon, April 27, 20262026-04-27
- 3.Mon, May 4, 20262026-05-04
- 4.Mon, May 11, 20262026-05-11
- 5.Mon, May 18, 20262026-05-18
- 6.Mon, May 25, 20262026-05-25
- 7.Mon, June 1, 20262026-06-01
- 8.Mon, June 8, 20262026-06-08
- 9.Mon, June 15, 20262026-06-15
- 10.Mon, June 22, 20262026-06-22
ICS Export
About RRULE Builder
RRULE Builder is a tool for visually constructing recurrence rules (RRULE) as defined in RFC 5545. An RRULE string can express complex schedules like "every Monday at 9 AM," "the first business day of the month," or "weekdays only for three months" in a single line of text. It is required when creating recurring events through calendar APIs such as Google Calendar or Microsoft Graph. Writing RRULE strings by hand is error-prone, but with a visual GUI you can configure each option clearly and instantly verify the result by previewing the next occurrences.
Key Features
- Build daily, weekly, monthly, and yearly recurrence patterns with a visual GUI
- Generate and preview RRULE strings in real time
- Preview up to 10 upcoming occurrences
- Export as ICS (iCalendar) file
Use Cases
- Building RRULE strings for Google Calendar API or Microsoft Graph API event creation
- Developing and testing scheduling features in calendar or booking applications
- Creating a recurring event ICS file for a weekly standup or monthly all-hands
- Learning RRULE syntax before writing it by hand in a calendar integration
- Generating and verifying complex patterns like 'every other Tuesday' or 'last Friday of the month'
- Bulk-creating recurring events and importing them into Outlook or Apple Calendar
FAQ
What is RRULE?
RRULE is a recurrence rule specification defined in RFC 5545. It is used by many calendar applications including Google Calendar, Outlook, and iCalendar.
Where can I use the generated RRULE?
You can use it with Google Calendar API, Microsoft Graph API, and any calendar system that supports iCalendar format. You can also export as an ICS file and import directly into calendar apps.
Can I preview more than 10 dates?
The preview shows the next 10 occurrences. In actual calendar applications, more dates can be expanded based on the RRULE string.
Can I select multiple days, like every Monday and Wednesday?
Yes, you can select multiple days using the BYDAY field. Combinations like Monday, Wednesday, and Friday are represented in a single RRULE string, for example: RRULE:FREQ=WEEKLY;BYDAY=MO,WE,FR.
What is the difference between RRULE and manually repeating events?
When you create events manually, changing the schedule later requires editing every occurrence individually. With RRULE, you can update all events sharing the same rule in one operation, which greatly improves efficiency for long-running recurring schedules.
Should I always set an end condition?
It depends on your use case. Some calendar APIs may experience performance issues when processing open-ended RRULEs. For long-running schedules, it is generally recommended to set a COUNT (number of occurrences) or UNTIL (end date) to keep processing predictable.