Public Holidays

The Public Holidays list (reachable from Setup) holds the dates the company observes as holidays, each with just a Date and a Description.

This list itself is just a plain record of dates — the calendar Business Central and Time Track Central actually calculate against is the Base Calendar set on Company Information (field Base Calendar Code). Public Holidays is how you get dates into that calendar without editing it directly; on its own, adding a row here doesn't do anything to calendars or capacity — three actions turn the list into actual effects:

Action	What it does
Upload ICS	Bulk-imports holidays from an .ics calendar file instead of entering them one by one — useful for importing a national holiday calendar each year.
Nonworking	Marks the selected date(s) as nonworking in Business Central's base calendar. Requires a Base Calendar Code to already be set on Company Information — set that first if this action errors.
Update Resource Capacity	Zeroes out resource capacity on the selected date(s) and recalculates capacity on any unlocked timesheets that span that date, so employees aren't shown as expected to work on a day now marked as a holiday.

A typical yearly routine is: import or enter next year's holidays, run Nonworking so the base calendar reflects them, then run Update Resource Capacity so existing open timesheets pick up the change immediately rather than waiting for their next recalculation.

Public holidays also interact with Overtime Lists — a line's Holiday flag applies its surcharge on these dates regardless of which day of the week they fall on.