Count an interval you can check
- Enter start and end dates, then choose elapsed days or both endpoints included.
- Choose calendar days, or switch to working days and select your weekend weekdays. Enter each holiday or closure as YYYY-MM-DD on its own line.
- Read the count and exclusion arithmetic. Browse the date-by-date audit, copy the summary, or export or print the complete interval.
Choose what the endpoints mean
For elapsed days, the selected dates form a start-included, end-excluded interval. Two identical dates therefore contain zero days. With both endpoints included, those same dates contain one day. A planning period needs that decision before any weekend exclusions are applied.
Calendar mode includes every date in that interval. Working mode excludes the weekdays you mark as weekends and the individual closure dates you enter. Choose Friday and Saturday, Saturday and Sunday, no weekend, or any other pattern your plan actually uses. The tool does not assume that a national holiday is observed on a nearby weekday.
Check the count before using it
For working days, the arithmetic is calendar dates − weekend dates − holiday dates + overlaps. Adding the overlap back prevents double subtraction. Holiday entries outside your interval are listed as ignored, and repeated entries are identified. An excluded end date is outside an elapsed interval even if it appears in your holiday list.
The screen shows 31 audit rows at a time. CSV export and printing include every date in the selected interval, with its weekday and inclusion or exclusion reason. Dates must be from 1900 through 2199, with at most 3,660 dates per interval and 2,000 holiday lines. Leap dates are validated; an impossible date is rejected rather than moved into the next month. Everything stays in this tab, and reset returns to the October 1–14 example with no added holidays.
Frequently asked questions
Why are October 1 to October 14 thirteen or fourteen days?
Elapsed mode includes October 1 and excludes October 14, giving 13 dates. Including both endpoints gives 14. The tool never silently changes that choice.
Are public holidays included automatically?
No. Holidays vary by country, region, organization and observed-date policy. Enter the actual closure dates that apply to your plan.
What if a holiday is also a weekend?
That date is excluded once. The summary shows weekend and holiday totals plus their overlap, and the audit labels the date as both. Duplicate holiday lines are counted once.
Do daylight saving changes affect the result?
No. The planner counts calendar dates using UTC day numbers, not local elapsed hours. It does not measure a 24-hour duration or a countdown to a particular time.
Can I use this for a contractual or legal deadline?
This planner does not implement jurisdictional, court, payroll or delivery rules. It counts dates according to the rules you select; use the governing rules for a formal deadline.