What Inclusive Dates Mean (With Examples)

A date range is inclusive when it counts its end date as part of the range, and exclusive when it stops at the start of the end date. An event running from Jan 1 to Jan 2 covers two full days if the range is inclusive, and only Jan 1 if it is exclusive.

Preceden treats the dates you enter as inclusive. When you add an event to your timeline, it's important to understand how Preceden will interpret the dates you specify.

When you specify an end date for your event, Preceden interprets that as you wanting the event to include that end date. For example, if a friend told you she was going to Europe from May to June, you'd likely assume that her trip includes June. Preceden does the same for the dates you enter. Put another way, Preceden interprets the event through the end date (or May through June in this example).

The exception is when the end date includes a time. If the same friend told you she had a dentist appointment from 1pm to 2pm, it's clear that she means the event only lasts an hour and Preceden does the same.

Here are a few examples to make this clear:

Two Day Event Span

Take the following event:

Start Date: Jan 1, 2015
End Date: Jan 2, 2015

Preceden interprets this to mean that the event ends at the end of Jan 2:

A day-scale timeline where the Event bar starts on Jan 1, 2015 and runs to the end of Jan 2, covering two full days

Single Day Event Span

Start Date: Jan 1, 2015
End Date: Jan 1, 2015

Then the event will span a single day:

The same day-scale timeline where the Event bar covers only Jan 1, 2015

Two Year Event Span

Start Date: 2015
End Date: 2016

Then Preceden will interpret it to mean that the event ends at the end of 2016:

A year-scale timeline where the Event bar starts in 2015 and runs to the end of 2016, covering two full years

One Year Event Span

Start Date: 2015
End Date: 2015

Which is identical to:

Start Date: Jan 1, 2015
End Date: Dec 31, 2015

Because the end date Dec 31, 2015 includes that day, the event spans the entire year:

The same year-scale timeline where the Event bar covers only 2015

End Dates That Include a Time

Start Date: Jan 1, 2015 1pm
End Date: Jan 1, 2015 2pm

Unlike the examples above that deal with dates, this end date specifies a time which Preceden interprets as the exact end time:

A timeline scaled to hours where the Event bar runs from the 1pm mark to the 2pm mark

Inclusive vs Exclusive Dates in Preceden

Two rules cover every case above:

An end date without a time is inclusive. Preceden runs the event through the end of that date, so Jan 2 means the end of Jan 2, and 2016 means the end of Dec 31, 2016.
An end date with a time is exact. Preceden uses the time you entered rather than extending the event, so 2pm means 2pm.

If you want an event to stop at the start of its end date, the way an exclusive range would, enter the previous day as the end date instead. An event that should cover only Jan 1 gets an end date of Jan 1, not Jan 2.