# Time and calendar

Instants, dates, durations, recurring rules and calendar events.

## Topics

| Page | What it covers |
|---|---|
| [Time and calendar additions](/docs/time-and-calendar-additions.md) | These types add to the time types: a time of day, a month, a week, a range of dates, an amount of calendar time, and the text forms of recurrences, opening hours and calendar events. |
| [Recurrences and opening hours](/docs/recurrences-and-opening-hours.md) | A `RecurrenceRule` says when something repeats, such as a class every Monday at 09:30. |
| [Calendar events](/docs/calendar-events.md) | A `CalendarEvent` is an entry in a calendar: a holiday, a booking, a shift. |

## Types

| Type | What it is |
|---|---|
| [`Instant`](/docs/types/type-instant.md) | One moment in time, the same everywhere in the world: `2026-10-25T09:30:00Z`. |
| [`CalendarDate`](/docs/types/type-calendar-date.md) | A day on the calendar, with no time or zone: `2026-10-25`. |
| [`ZonedTime`](/docs/types/type-zoned-time.md) | A moment seen on the clock in one place: `2026-10-25T09:30:00+00:00[Europe/London]`. |
| [`Duration`](/docs/types/type-duration.md) | An exact length of time, to the millisecond: 90 minutes is `PT1H30M`. |
| [`Weekday`](/docs/types/type-weekday.md) | A day of the week: `monday` to `sunday`. |
| [`LocalTime`](/docs/types/type-local-time.md) | A time on the clock, with no date or zone: `09:30:00`. |
| [`LocalDateTime`](/docs/types/type-local-date-time.md) | A date and a clock time with no zone: `2026-10-25T09:30:00`. |
| [`Month`](/docs/types/type-month.md) | A month of the year: `january` to `december`. |
| [`YearMonth`](/docs/types/type-year-month.md) | One month of one year: `2026-10`. |
| [`Year`](/docs/types/type-year.md) | A calendar year: `2026`. |
| [`Quarter`](/docs/types/type-quarter.md) | A quarter of a calendar year: `2026-Q4`. |
| [`IsoWeek`](/docs/types/type-iso-week.md) | A numbered week of a year, as ISO 8601 counts them: `2026-W43`. |
| [`UtcOffset`](/docs/types/type-utc-offset.md) | A fixed gap from UTC, in minutes: `+05:30`. |
| [`DateRange`](/docs/types/type-date-range.md) | The days from one date to another, both included: `2026-10-01/2026-10-31`. |
| [`InstantRange`](/docs/types/type-instant-range.md) | The moments from a start up to, but not including, an end. |
| [`CalendarPeriod`](/docs/types/type-calendar-period.md) | An amount of calendar time in years, months and days: `P1Y2M10D`. |
| [`RecurrenceRule`](/docs/types/type-recurrence-rule.md) | When something repeats, in the calendar standard's own text. |
| [`OpeningHours`](/docs/types/type-opening-hours.md) | When a place is open each week, and the days that differ. |
| [`CalendarEvent`](/docs/types/type-calendar-event.md) | A calendar event, as a calendar app reads one: a title, and its days or its times. |