DTEND

DTEND is a property in the iCalendar data model (RFC 5545) that specifies the end date and time of a calendar component, such as a VEVENT or VTODO. It works together with DTSTART to define the duration of the component. The value of DTEND can be either a date (VALUE=DATE) for all-day events or a date-time value for events with a specific time. When a date-time value is used, it may include a time zone (via the TZID parameter) or be in Coordinated Universal Time (UTC) indicated by a trailing Z.

For all-day events, DTEND is typically expressed as a date and represents the day after the last day of the event. For example, a one-day all-day event on January 1 would use DTSTART;VALUE=DATE:20240101 and DTEND;VALUE=DATE:20240102. For timed events, the end time can be given in local time with a TZID or in UTC; examples include DTEND:20240101T170000Z or DTEND;TZID=America/New_York:20240101T140000.

DTEND can be omitted if DURATION is provided instead, in which case the duration between DTSTART and the end is determined from DURATION. The DTEND value must represent a moment later than DTSTART for most use cases; some implementations allow zero-duration events, but the standard emphasizes a definite end moment.

In practice, applications use DTEND to render event length, schedule conflicts, and time zone conversions, and it is commonly discussed alongside DTSTART, DURATION, and VALUE to define the temporal extent of calendar components.