DTSTART19970714T170000Z

DTSTART is a property in the iCalendar data format (RFC 5545) that specifies the starting date and time of a calendar component, such as an event or task. In ICS syntax, the value is typically written as DTSTART:YYYYMMDDTHHMMSS[Z] (for UTC) or with a time zone identifier if local time is used. The Z suffix indicates Coordinated Universal Time (UTC).

The example 19970714T170000Z encodes July 14, 1997 at 17:00:00 UTC. In standard ICS files, this would appear as a line such as DTSTART:19970714T170000Z. The time zone indicator (Z) clarifies that the time is in UTC and not relative to a local zone. In some plain-text references, the property and value may appear concatenated as "DTSTART19970714T170000Z," but the formal ICS syntax uses the colon to separate the property name and its value.

DTSTART is commonly paired with a corresponding DTEND to indicate the event duration, and may be combined with RRULE to express recurrence rules. All-day events are represented with a date value (YYYYMMDD) and often use the VALUE=DATE parameter, for example DTSTART;VALUE=DATE:19970714.

Understanding DTSTART values is essential for interoperability of calendar data across applications that use the iCalendar format. See also iCalendar, RFC 5545, VEVENT, and ICS file format.