Custom Holiday Business Day Calculator

How the Custom Holiday Business Day Calculator works

The Custom Holiday Business Day Calculator counts working days between two dates using the calendar your organization actually keeps, not just the one the government publishes. Alongside the built-in public holiday sets for the countries you select, you paste your own closure dates — company shutdowns, floating holidays, regional observances, plant maintenance days — one per line, and every one of them is excluded from the count exactly as a public holiday would be.

This matters because standard business-day math stops at the official calendar. A team that goes dark between Christmas and New Year, a factory with a summer retooling week, or an office that observes a local fair day all have fewer real working days than any country-level holiday list suggests — and a project plan built on the inflated count is optimistic before work even starts.

Custom closures follow the same rules as public holidays: a closure that lands on a weekend costs nothing (the day was already excluded), and a closure that coincides with a public holiday is not double-counted — a day can only be removed from the count once. The result includes a breakdown into business days, weekend days, and holiday days so you can verify each closure landed where you expected. You can also switch the workweek preset for non Monday-to-Friday operations and choose whether the start and end dates themselves count.

Worked example

A team planning December 1–31 in a country that observes December 25 also shuts down December 28–31. Entering those four dates as custom holidays alongside the built-in calendar removes the public holiday and the four shutdown weekdays from the count (any shutdown date falling on a weekend costs nothing extra), turning a naive 22-working-day December into the roughly 18 days the team really has.

Frequently asked questions