What happens if a blackout date falls outside every window?

It has no effect on the result, since only blackout dates that actually fall inside the computed intersection are removed from the eligible ranges.

Can the eligible result be split into more than two ranges?

Yes, each blackout date inside the intersection can split the eligible range again, so several scattered blackout dates can produce several separate eligible ranges.

Date Window Intersection Planner

Enter several labeled open and close windows to find the dates that satisfy all of them at once, then remove any blackout dates that fall inside that shared window. Every window is half-open, so its start date counts and its end date does not.

Comparing named single dates instead of open and close windows? See Earlier-of / Later-of Date Solver.

Worked example

A window open from January 1 through January 10 and a second window open from February 1 through February 10 share no common date at all, since the latest start across both windows falls after the earliest end across both windows. The planner reports this plainly as no eligible date, rather than an empty or confusing result. Two overlapping windows that do share real dates, with a single blackout date landing right in the middle of that shared range, produce two separate eligible date ranges instead of one continuous range, split cleanly around the excluded day.

Common mistakes

Forgetting that each window's end date is excluded, which can make an intersection look one day narrower than expected if the end dates were meant to be inclusive.
Entering only one window. At least one is required, but the real value of this tool shows up once two or more windows need to agree at once.

Limitations

This computes a pure date intersection and blackout removal only. It does not weigh which window is more important than another, and it makes no scheduling or legal determination beyond the stated windows and blackout dates.

Frequently asked questions

What happens if a blackout date falls outside every window?: It has no effect on the result, since only blackout dates that actually fall inside the computed intersection are removed from the eligible ranges.
Can the eligible result be split into more than two ranges?: Yes, each blackout date inside the intersection can split the eligible range again, so several scattered blackout dates can produce several separate eligible ranges.