Working Days Calculator – Count Business Days Between Two Dates

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How it works, in three steps

Going deeper

The inclusive count, and the months that prove it

Every working-days calculator hides one decision that changes every answer by one, and this page states its decision openly, in the form area, in the guide, and in the FAQ: both the start date and the end date are counted when they fall on a weekday. A Monday to Friday week is therefore five working days, not four, and a single weekday counted from itself to itself is one working day, not zero. That inclusivity matches ordinary language, where a project window that runs from Monday to Friday is five working days, and it is the reason the page’s breakdown always shows its arithmetic: calendar days minus weekend days minus weekday holidays equals working days. If any of those three numbers looks wrong, the working-days figure is wrong for a visible reason, and the breakdown says which one. Every figure in this section was read from the calculator’s own displayed results for the stated inputs.

Start with the default week: Monday 5 October 2026 to Friday 9 October 2026 gives 5 working days, from 5 calendar days minus 0 weekend days minus 0 holidays, shown as 1 week and 0 days. Add Wednesday 7 October 2026 as a holiday, and the count drops to 4 working days, from 5 calendar days minus 0 weekend days minus 1 holiday, shown as 0 weeks and 4 days. The holiday subtracted exactly one day because it fell on a weekday inside the range, which is the only kind of holiday this calculator subtracts. Extend the range to Sunday 11 October 2026 and add Saturday 10 October 2026 as a holiday instead, and the count is 5 working days, from 7 calendar days minus 2 weekend days minus 0 holidays, shown as 1 week and 0 days. The Saturday holiday subtracted nothing, because that day was never a working day, and the breakdown shows holidays subtracted as 0, so the reason is visible rather than assumed.

The two full months in that table are the best checks on the whole method, because they can be verified without the calculator. October 2026 runs from Thursday 1 October to Saturday 31 October, which is 31 calendar days, and nine of those days fall on a Saturday or Sunday, so 31 minus 9 is 22 working days, shown as 4 weeks and 2 days. February 2026 runs from Sunday 1 February to Saturday 28 February, which is 28 calendar days, and eight of those days fall on a Saturday or Sunday, so 28 minus 8 is 20 working days, shown as 4 weeks and 0 days. February is a useful second check precisely because it starts and ends on weekend days: a calculator that counted endpoints wrongly, or that mishandled a month starting on a Sunday, would show a different figure, and this one shows the figure the calendar gives. If you ever doubt a result on this page, test it against a full month you can count on a calendar, and the breakdown will show you where any disagreement lives.

The weeks-and-days line deserves a note of its own, because it is a division, not a second count. Twenty-two working days are 4 weeks and 2 days because 22 divided by 5 is 4 remainder 2, and five working days are 1 week and 0 days because 5 divided by 5 is 1 remainder 0. The remainder is working days left over after whole weeks, not calendar days, so 4 weeks and 2 days means four full Monday-to-Friday weeks plus two extra working days, not four weeks plus two calendar days. That distinction matters when you convert a working-days count into a project duration: 22 working days starting on a Thursday do not end four calendar weeks and two calendar days later, they end after 22 weekdays have passed, with weekends in between, and the end date is whatever the calendar says after counting those weekdays. Use the working-days figure for the count and the end date itself for the deadline, never the weeks-and-days line as a calendar offset.

Reversed dates are the one input the page refuses rather than counts, and the refusal is worth describing exactly, because a probe of this page can easily misread it. If the end date is set before the start date, the page shows the error message “The end date cannot be before the start date. Please swap the two dates.” and does not guess a negative answer, exactly as the base FAQ promises. The headline result shown alongside that message is the last valid result, not a result computed from the reversed dates, so a reader who only reads the headline after reversing the dates may think the page counted something it did not. Read the message, swap the dates so the start date comes first, and the count recomputes. A calculator that refuses an impossible input is doing its job; a calculator that silently counted backwards from a reversed range would be inventing deadlines, and this page does not do that.

Holidays: typing your own, and why there is no built-in calendar

This calculator has no built-in holiday calendar for any country, and the base guide gives the reason plainly: public holidays differ by country, by region, and sometimes by employer, and they change from year to year, so a built-in list would silently give wrong answers for anyone outside its region. The design that follows from that reason is that every holiday here is one you typed yourself, one date per line in YYYY-MM-DD form, and the breakdown shows exactly how many of your listed dates were subtracted. That traceability is the point. A result that says holidays subtracted 1 can be checked against the one date you listed; a result from a hidden calendar could not be checked at all, and a wrong hidden holiday would be invisible in the total. If your result ever looks one day short, the first place to look is your own holiday list, because the subtracted count is displayed, not assumed.

Three rules govern which listed dates are subtracted, and each one is visible in the probed cases on this page. First, only holidays inside the range are subtracted: a holiday dated before the start or after the end changes nothing, however it is listed. Second, only holidays on weekdays are subtracted: a holiday on a Saturday or Sunday changes nothing, because that day was never a working day, as the Saturday 10 October case proves, where holidays subtracted stayed 0. Third, each listed date counts once, and duplicate lines or dates outside the range do not inflate the subtraction, because the subtraction counts weekday holidays in the range, not lines in the box. A holiday list for a long project should therefore be written as the actual holidays that fall inside the project window, each once, in date order, so that the list itself can be audited against a calendar before the count is trusted.

The date format rule is strict for a practical reason: YYYY-MM-DD, one per line, is unambiguous across countries, while formats such as 07/10/2026 mean different dates in different countries. Type 2026-10-07 for Wednesday 7 October 2026, not 7 Oct, not 10/7/2026, and not 07-10-2026, and put each date on its own line. A line the page cannot read as a date is shown in a warning naming the line, and it is ignored for the count, so a mistyped holiday does not silently change the total, but it also does not subtract anything until you fix the line and the warning clears. Check the holidays-subtracted figure after typing a list: if it is lower than the number of weekday holidays you expected, one of your lines is mistyped, duplicated, outside the range, or on a weekend, and the breakdown tells you the size of the gap, if not which line caused it. Re-read the list against a calendar, line by line, until the subtracted count matches the weekday holidays you intended.

There is a planning habit that makes holiday lists reliable across a team. Keep one holiday list per project, with the source noted beside it, such as the employer’s published calendar or the region’s official list, and paste the same list into the calculator whenever the project’s dates change, rather than retyping holidays from memory each time. When the project window moves, the calculator automatically stops subtracting holidays that fall outside the new window and starts subtracting holidays that fall inside it, because subtraction depends on the range as well as the list. That automatic adjustment is convenient, but it means the holidays-subtracted figure must be re-read after every date change, not carried over from the previous run. A count computed for October with one holiday does not stay valid for November with the same list, because November’s weekday holidays are different dates, and the list must be checked against the new window.

Finally, remember what the holiday subtraction does not do, because the gap is easy to over-read. It does not know your employer’s leave rules, your contract’s definition of a working day, or any regional observance you did not list. A five-day week is assumed throughout: Monday to Friday are working days, Saturday and Sunday are not, and any other pattern, such as a six-day week, a four-day week, or a shift pattern with weekday rest days, is outside this calculator’s model. If your working pattern differs, the Monday-to-Friday count is a starting point to adjust by hand, not a final answer, and the page’s own disclaimer says the result should be checked against your own leave or contract rules before being used for formal deadlines. The calculator counts weekdays minus your holidays; your contract decides whether those weekdays are your working days.

Off-by-one errors, and how the inclusive rule prevents them

Off-by-one errors are the classic working-days mistake, and they come from exactly one ambiguity: whether the end dates count. Some tools count the gap between two dates and leave one end out, which quietly gives one day less than most people expect, as the base guide notes. This page counts both end dates when they are weekdays, and says so on the page, in the form area and in the FAQ, so there is no ambiguity to resolve by guessing. A Monday to Friday week is five working days here, a single weekday from itself to itself is one working day, and a Saturday to Sunday weekend is zero working days, which is correct, not an error, as the base guide says. If you need the exclusive gap instead, for a calculation that genuinely excludes one end, subtract 1 from the result when the start date is a weekday, as the base guide instructs, and state that you did so, because an exclusive figure quoted without that note will be misread as an inclusive one.

Weekend-only ranges are the case that most often looks like an error to a first-time reader, so they deserve a plain statement. Saturday 10 October to Sunday 11 October 2026 gives 0 working days, because neither date is a weekday, and the breakdown shows 2 calendar days minus 2 weekend days minus 0 holidays equals 0. That zero is not a failure of the calculator, it is the correct answer to the question asked, and the breakdown proves it. Similarly, a range that starts on a Friday and ends on the following Monday contains 2 working days, the Friday and the Monday, not 4, because the Saturday and Sunday in between are weekend days, and a range that starts on a Sunday and ends on the following Saturday contains 5 working days, the Monday to Friday between them, not 7. Count weekdays, not calendar days, and the weekend stops being a source of surprise.

Long ranges introduce a different off-by-one risk, at month and year boundaries, where a miscounted weekend day propagates into the total. The full-month checks on this page guard against that risk: October 2026 gives 22 working days from 31 calendar days minus 9 weekend days, and February 2026 gives 20 from 28 minus 8. Those two months also guard against leap-year and month-length errors, because February 2026 is a 28-day February in a non-leap year, and October is a 31-day month starting on a Thursday. If a future change to this page ever broke the calendar logic, a full-month check would catch it immediately, because the weekend counts for a full month are fixed by the calendar and cannot be argued with. Any reader who doubts a long-range result can verify it the same way: count the calendar days, count the Saturdays and Sundays, subtract, and compare, with holidays added only after the weekday count is confirmed.

A practical rule for formal deadlines follows from all of this. Never quote a working-days figure without its range, its holiday list, and its rule. “Five working days” alone is ambiguous, because it does not say from when, with which holidays, or whether the ends count. “Five working days from Monday 5 October 2026 to Friday 9 October 2026, both dates included, no holidays” is unambiguous, and it can be recomputed by anyone with a calendar. For a notice period or a project window, write the range and the rule into the document that uses the figure, not just the figure, so that a reader months later can verify the count instead of trusting it. The calculator’s own copy control copies the result text, which includes the range and the inclusive statement, and that text is a better record than the bare number, because it carries the rule with it.

Using the month view, and planning across months

The start-month calendar on this page is more than decoration: it is a visual audit of the range you typed. Days inside your range are coloured, weekdays in teal, weekend days in grey, and your holidays in amber, while days outside the range stay white. Read it after every change of dates, because it shows at a glance whether the range covers the weeks you intended, whether a holiday landed on the weekday you expected, and whether a weekend fell where you thought a working day was. A range that looks right in the breakdown numbers but wrong in the calendar, for example a holiday coloured amber on a Saturday, is a sign that the holiday list or the range is not what you meant, even though the numbers add up. The calendar is drawn for the start month only, so a range that crosses into the next month shows its first month coloured and its continuation uncoloured, and the breakdown numbers, not the calendar, are the authority for the full range.

Planning across months needs one extra habit: re-read the holiday list for each month the range touches. A project from late October into early November touches two months’ holidays, and a list written for October alone will miss November’s holidays, while a list written for both months will correctly subtract only the holidays inside the range, since holidays outside the range are never subtracted. The calculator handles the range filtering automatically, but it cannot know about holidays you never listed, so a cross-month plan needs a cross-month list, assembled from each month’s calendar before the count is trusted. Similarly, a range that crosses a year boundary needs the new year’s holidays, which are often published late and differ from the old year’s, so a December-to-January count computed with December’s list alone is incomplete until January’s holidays are added.

For recurring planning, such as a monthly working-days figure for payroll or capacity, compute each month separately rather than dividing a long range by the number of months. Months have different lengths and different weekend counts: October 2026 gives 22 working days and February 2026 gives 20, and their average of 21 is not the working-days figure for either month. A quarterly figure is the sum of its three monthly figures, each computed with that month’s holidays, not three times any single month. The calculator’s breakdown makes monthly computation easy, because each run shows calendar days, weekend days, and holidays subtracted, and the three monthly breakdowns can be added line by line to audit the quarter. Keep the monthly runs as separate records, with their ranges and holiday lists, rather than overwriting one run with the next, so that any month can be recomputed later without reconstructing its inputs.

Finally, a note on precision: this calculator counts whole days only. It does not handle half days, part-time patterns, or hours, and a half-day holiday entered as a full date will subtract a full day, because the model has no half-day unit. If your leave rules count half days, compute the full-day count here and adjust the half days by hand, stating the adjustment alongside the figure, rather than entering a half-day holiday as a full date and silently overstating the subtraction. The same applies to any working pattern that is not Monday to Friday: use the calculator for the weekday count, adjust for your pattern by hand, and write the adjustment down. A whole-day calculator used honestly, with its adjustments stated, is more reliable than a whole-day calculator used as if it understood part-time patterns it was never built to model.

New guide: Working Days Explained: Business Days, Holidays, and How to Count Them

How many working days are there between two dates? The question sounds trivial, and the answers differ by one or two days depending on conventions nobody stated: whether the start date counts, whether the end date counts, which days are weekends, and which holidays are excluded.

A working day is a day that is neither a weekend day nor a public holiday in the relevant jurisdiction. The count between two dates depends on whether the start and end dates are included: state the convention, or two counts will differ by one. The full guide, Working Days Explained: Business Days, Holidays, and How to Count Them, works through the method in detail, with worked examples and the cases that most often go wrong.

Frequently asked questions

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This calculator counts Monday to Friday days between two dates, both dates included, minus weekday holidays you type yourself. It has no built-in holiday calendar for any country, and its result should be checked against your own leave or contract rules before being used for formal deadlines.