Use this calendar tool when the calendar system, inclusivity rules, time zone, recurrence convention, and holiday inputs are explicit.

Start date

Required string. First occurrence as an ISO date YYYY-MM-DD.

Frequency

Required string. Recurrence frequency.

Interval

Optional integer. Step size between occurrences (at least 1).

Count

Optional integer. Number of occurrences to generate (1 to 52).

The cited overview of Calendar date supplies background for the terminology and domain context used by this tool.^[1]

Generate recurring dates from a start date with daily/weekly/monthly/yearly frequency and interval; monthly and yearly steps clamp to the last valid day of the target month. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Occurrences

Returned list. Occurrences as ISO dates, starting at the start date.

• Civil calendars, holidays, daylight-saving transitions, month-end clamping, and jurisdiction-specific business-day rules can produce different valid interpretations.
• Interval must be at least 1.
• Interval must be no greater than 1000.
• Count must be at least 1.
• Count must be no greater than 52.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

Store unambiguous ISO dates and zone identifiers, and verify official calendars or a standards-compliant scheduling library for operational use.

• End of Month Tool

  Return the last day of the month of an ISO calendar date.

• Start of Month Tool

  Return the first day of the month of an ISO calendar date.

• Year Calendar

  Generate a Monday-first calendar for all 12 months and mark the ISO week containing an optional date. Dates are interpreted in UTC to avoid local time-zone shifts.