Or “how long is an event that does not have an end date?”
When creating an event, you can enter the start date and end date. Unless you check the “All day event” checkbox, you can also specify start and end time.
If you enter only a start date or a start date and time, the event will never end and will always be upcoming.
If you enter a start date and time and an end date and time, the event will be upcoming until the end date and time.
If you enter a start date, a start time and an end time, we will assume the event ends the same day as it started, at the end time. The end time need to be after the start time.
If you check the “all day event” checkbox, and only enter the start date, the event will be upcoming until the end of that day. If you enter two separate dates, the event will end at the end of day on the end date.
If you enter a end time, you need to enter a start time.