Irish Calculators
Work & pay

Business Days Between Dates Calculator

Count working days over a chosen date range and decide whether to include either endpoint. Supply the holidays and closures your workplace observes; no public-holiday calendar is assumed.

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Your numbers

One YYYY-MM-DD per line. Add public holidays or closures that your business actually observes.
Your figures stay on this device.

How the calculation works

This tool counts eligible dates within a date range using both a working-week pattern and your own closure list. It makes endpoint inclusion explicit, which is often the source of a one-day difference between otherwise similar calculations.

Iterate the selected date boundaries; count dates in the chosen working week unless they appear in the excluded-date list.

  1. Select the calendar boundaries

    Start with the real start and end dates, then remove either boundary according to the selected convention. The end cannot precede the start.

  2. Apply the working-week pattern

    Check each remaining date against the chosen weekday pattern. A six-day week excludes Sunday; the seven-day option initially treats every date as eligible.

  3. Remove listed closures

    Any eligible date appearing in the exclusion list is omitted. A closure already outside the working week does not cause an additional deduction.

Worked example: Full working week

Sample inputs demonstrate the method. They are not a forecast or product offer.

The first example spans Monday 5 October through Friday 9 October 2026, includes both endpoints and uses Monday to Friday. With no closures, all five selected dates qualify, so the result is five business days.

Start date
2026-10-05
End date
2026-10-09
Count boundaries
Include start and end
Working week
Monday to Friday
Additional non-working dates

Expected result

Business days
5
Worked example: One closure

Sample inputs demonstrate the method. They are not a forecast or product offer.

Start date
2026-10-05
End date
2026-10-09
Count boundaries
Include start and end
Working week
Monday to Friday
Additional non-working dates
2026-10-07

Expected result

Business days
4

Understanding your result

Business days is the final count after both filters. The calendar-day breakdown counts the selected boundaries before weekends and closures are removed.

No Irish holiday calendar or substitute-day rule is silently supplied. The exclusion list is essential when the result is intended to follow a specific workplace or contractual calendar.

Questions you might have

What does this business days between dates calculator include?

Count working days between dates with an explicit working week, boundary convention and your actual holiday or closure dates.

Which assumptions should I check?

No public-holiday calendar is silently assumed. Add the dates your workplace observes; a weekend public holiday does not establish which substitute day your business closes.

Choosing the right inputs

Count boundaries
Choose whether to count the start, end, both or neither. Including an endpoint only makes it eligible for assessment; a weekend or excluded closure still does not count as a working day.
Working week
The supported patterns are Monday to Friday, Monday to Saturday, or every day. A custom rotating weekly roster is not inferred.
Additional non-working dates
Supply observed holidays and closures as YYYY-MM-DD dates, one per line. Use the dates your organisation actually treats as non-working.

Common mistakes to avoid

  • Do not include a closure merely because it appears on a public calendar if your relevant business does not observe that date.
  • A same-day range counts one date only when both boundaries are included and that date is eligible.

Assumptions to check

  • No public-holiday calendar is silently assumed. Add the dates your workplace observes; a weekend public holiday does not establish which substitute day your business closes.

Sources and method

Read our calculation and testing approach.