Business Days in September 2027 for Ireland
September 2027 has 22 working days under the Irish holiday calendar. September 2027 contains no Irish holidays on a weekday. The month covers 30 calendar days, of which 8 are Saturday and Sunday. That count drives invoice cycles, payroll runs, and any contract that defines deadlines as a number of working days in Ireland.
working days
22
Calendar Days
30
Weekend Days
8
holidays
0
Work Weeks
4.4
| Sun | Mon | Tue | Wed | Thu | Fri | Sat |
|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 wknd | |||
5 wknd | 6 | 7 | 8 | 9 | 10 | 11 wknd |
12 wknd | 13 | 14 | 15 | 16 | 17 | 18 wknd |
19 wknd | 20 | 21 | 22 | 23 | 24 | 25 wknd |
26 wknd | 27 | 28 | 29 | 30 |
holidays in September 2027
No Irish holidays fall on a weekday in September 2027, so the month loses no working day to a holiday on this calendar.
Ireland September deadlines
VAT for the July-August period is due by September 19, or September 23 on ROS. A company with a 31 December year end files its CT1 return and pays any balance on or before September 23, the 23rd of the ninth month after its accounting period ends. Employers pay August's PAYE liability within 14 days after the end of the month, or 23 days on ROS. September has no Irish public holiday.
Sources for these dates
- When VAT becomes payable: file and pay VAT by the 19th day of the month following the end of each taxable period, extended to the 23rd day of the month for ROS filers; the taxable period is a two-month period commencing on the first day of January, March, May, July, September and November (Revenue (Office of the Revenue Commissioners))
- Paying tax to Revenue: the monthly statement shows the employer's total tax liability for the reference month based on payroll submissions during that month; the employer must pay within 14 days after the end of each month, or 23 days after the end of the month if it files and pays on ROS (Revenue (Office of the Revenue Commissioners))
- Corporation Tax payment and filing: a company must file its return, and pay any tax due, nine months after the end of the accounting period, on or before the 23rd of the ninth month (the 21st where it does not pay and file electronically) (Revenue (Office of the Revenue Commissioners))
- Public Holidays: the ten public holidays and their 2026 dates; the benefit for a public holiday is a paid day off on that day, a paid day off within a month, an additional day of annual leave or an additional day's pay; where the holiday falls on a Saturday or Sunday, in the Commission's words, there is no legal entitlement to have the next working day off work; Good Friday is not a public holiday (Workplace Relations Commission)
Checked October 9, 2026. All sources
Those dates in 2027
One of the dates named above does not fall on a working day in 2027 under the Irish calendar. A fixed calendar date advances through the week year by year, so this resolution holds for 2027 only.
| Date | Weekday | Status under the Irish calendar | First working day on or after |
|---|---|---|---|
| September 19 | Sunday | Weekend | September 20, 2027 |
| September 23 | Thursday | Working day |
This table resolves weekdays and nothing else. Whether an obligation actually moves when its date is not a working day is set by the instrument that creates it, and no shift rule is assumed here for any jurisdiction. The sources behind each calendar are listed in the source register.
Day-of-Week Distribution
The count of each weekday in September 2027. Useful for shift scheduling, weekly recurring billing, and any rota that depends on a specific day of the week landing in-month.
| Day | Count |
|---|---|
| Monday | 4 |
| Tuesday | 4 |
| Wednesday | 5 |
| Thursday | 5 |
| Friday | 4 |
| Saturday | 4 |
| Sunday | 4 |
Ireland reporting cycles and business-day rules
Revenue sets Irish VAT on two-month taxable periods starting in January, March, May, July, September and November: the return and payment are due by the 19th day of the month after each period, extended to the 23rd for ROS filers. An employer's monthly PAYE liability, shown on a Revenue statement built from the month's payroll submissions, is due 14 days after the end of the month, or 23 days for employers who file and pay on ROS. A company files its CT1 return and pays any balance nine months after the end of its accounting period, on or before the 23rd of the ninth month (the 21st if it does not file and pay electronically). T2, the Eurosystem's real-time gross settlement system, which replaced TARGET2 in March 2023, is open Monday to Friday and, for euro settlement, also closed on 1 January, Good Friday, Easter Monday, 1 May, 25 December and 26 December. It does not close for St Patrick's Day (17 March) or for the Irish public holidays in February, June, August and October, and it does close on 1 May, which is an Irish public holiday only when it is the first Monday in May. Under the European Communities (Late Payment in Commercial Transactions) Regulations 2012, as amended in 2013, 2014 and 2016, statutory late payment interest is the ECB main refinancing rate plus 8 percentage points; between undertakings a contract may vary that interest, provided the result is not grossly unfair to the creditor. A payment date or period that a contract between undertakings sets beyond 60 calendar days must be expressly agreed and not grossly unfair to the supplier. Where the contract specifies no date or period for payment, the payment date falls 30 calendar days after the purchaser receives the invoice, after delivery where the invoice arrives first or its date of receipt is uncertain, or after an acceptance or verification procedure where one applies and the invoice arrives no later than it. Interest runs from the day after the payment date.
Sources for these rules
- When VAT becomes payable: file and pay VAT by the 19th day of the month following the end of each taxable period, extended to the 23rd day of the month for ROS filers; the taxable period is a two-month period commencing on the first day of January, March, May, July, September and November (Revenue (Office of the Revenue Commissioners))
- Paying tax to Revenue: the monthly statement shows the employer's total tax liability for the reference month based on payroll submissions during that month; the employer must pay within 14 days after the end of each month, or 23 days after the end of the month if it files and pays on ROS (Revenue (Office of the Revenue Commissioners))
- Corporation Tax payment and filing: a company must file its return, and pay any tax due, nine months after the end of the accounting period, on or before the 23rd of the ninth month (the 21st where it does not pay and file electronically) (Revenue (Office of the Revenue Commissioners))
- What is T2?: T2 is the Eurosystem's real-time gross settlement (RTGS) system; it is open from Monday to Friday and, for euro settlement, also closed on 1 January, Good Friday, Easter Monday, 1 May, 25 December and 26 December; T2 was launched in March 2023, replacing TARGET2 (European Central Bank)
- Public Holidays: the ten public holidays and their 2026 dates; the benefit for a public holiday is a paid day off on that day, a paid day off within a month, an additional day of annual leave or an additional day's pay; where the holiday falls on a Saturday or Sunday, in the Commission's words, there is no legal entitlement to have the next working day off work; Good Friday is not a public holiday (Workplace Relations Commission)
- S.I. No. 580 of 2012, European Communities (Late Payment in Commercial Transactions) Regulations 2012, as made: regulation 2(1), relevant payment date; regulation 5(1), the ECB main refinancing rate plus 8 percentage points. Amended by S.I. No. 74 of 2013, S.I. No. 196 of 2014 and S.I. No. 281 of 2016 (Irish Statute Book)
- S.I. No. 74 of 2013, European Communities (Late Payment in Commercial Transactions) (Amendment) Regulations 2013, regulation 2: regulation 4 substituted; 4(2), interest for the period beginning on the day after the relevant payment date (Irish Statute Book)
- S.I. No. 196 of 2014, European Communities (Late Payment in Commercial Transactions) (Amendment) Regulations 2014, regulation 2: relevant payment date, 30 calendar days after the later of receipt of the invoice or delivery, or after an acceptance or verification procedure; regulation 5(1) now subject to paragraph (3); regulation 5(3), between undertakings the parties may vary the interest provided it is not grossly unfair to the creditor (Irish Statute Book)
- S.I. No. 281 of 2016, European Communities (Late Payment in Commercial Transactions) (Amendment) Regulations 2016, regulation 3: the definition of relevant payment date in regulation 2(1) amended; paragraph (a) substituted: between undertakings a date or period for payment that exceeds 60 calendar days must be expressly agreed in the contract and not be grossly unfair to the supplier (Irish Statute Book)
- Legislation Directory, statutory instruments of 2012, as read on 2026-10-13 (updated to 17 September 2026): S.I. No. 580 of 2012 is affected in its text by S.I. No. 74 of 2013 (regulation 4 substituted), S.I. No. 196 of 2014 (regulations 2(1), 4 and 5 amended) and S.I. No. 281 of 2016 (regulation 2(1) amended), and by no later amending instrument (Irish Statute Book (Legislation Directory))
Checked October 13, 2026. All sources
September 2027 working days compared by country
Working-day counts vary across countries because each country observes its own public holidays. The table below shows September 2027 under 11 of the site's 25 holiday calendars; the summary above gives Ireland's own count.
| Country | Business Days | Holidays this month |
|---|---|---|
| 🇺🇸United States | 21 | Labor Day |
| 🇬🇧United Kingdom | 22 | None |
| 🇨🇦Canada | 20 | Labour Day, National Day for Truth and Reconciliation |
| 🇦🇺Australia | 22 | None |
| 🇮🇳India | 22 | None |
| 🇵🇭Philippines | 22 | None |
| 🇫🇷France | 22 | None |
| 🇩🇪Germany | 22 | None |
| 🇯🇵Japan | 20 | Respect for the Aged Day, Autumnal Equinox Day |
| 🇲🇽Mexico | 21 | Día de la Independencia |
| 🇸🇬Singapore | 22 | None |
How September 2027 compares year over year
September 2026 also had 22 working days, so the working capacity is unchanged year over year. On the surrounding months, August 2027 has 21 working days and October 2027 has 20. Looking forward, September 2028 has 21 working days under the same Irish holiday calendar.
Using this calculator in Ireland
Count the 22 business days of September 2027 against Revenue's dates when one is near: VAT for each two-month period is due by the 19th day of the following month, or the 23rd for ROS filers; an employer's PAYE for a month within 14 days after its end, or 23 days on ROS; and a company's CT1 return and balance on or before the 23rd of the ninth month after its accounting period ends (the 21st if it does not file and pay electronically). A euro payment that settles through T2 cannot settle on 1 January, Good Friday, Easter Monday, 1 May, 25 December or 26 December, although T2 does not close for St Patrick's Day or for the Irish public holidays in February, June, August and October. Where a contract specifies no date or period for payment, the Late Payment Regulations 2012, as amended, put the payment date 30 calendar days after the purchaser receives the invoice, after delivery where the invoice arrives first or its date of receipt is uncertain, or after an acceptance or verification procedure where one applies and the invoice arrives no later than it.
Sources for these rules
- When VAT becomes payable: file and pay VAT by the 19th day of the month following the end of each taxable period, extended to the 23rd day of the month for ROS filers; the taxable period is a two-month period commencing on the first day of January, March, May, July, September and November (Revenue (Office of the Revenue Commissioners))
- Paying tax to Revenue: the monthly statement shows the employer's total tax liability for the reference month based on payroll submissions during that month; the employer must pay within 14 days after the end of each month, or 23 days after the end of the month if it files and pays on ROS (Revenue (Office of the Revenue Commissioners))
- Corporation Tax payment and filing: a company must file its return, and pay any tax due, nine months after the end of the accounting period, on or before the 23rd of the ninth month (the 21st where it does not pay and file electronically) (Revenue (Office of the Revenue Commissioners))
- What is T2?: T2 is the Eurosystem's real-time gross settlement (RTGS) system; it is open from Monday to Friday and, for euro settlement, also closed on 1 January, Good Friday, Easter Monday, 1 May, 25 December and 26 December (European Central Bank)
- Public Holidays: the ten public holidays and their 2026 dates; the benefit for a public holiday is a paid day off on that day, a paid day off within a month, an additional day of annual leave or an additional day's pay; where the holiday falls on a Saturday or Sunday, in the Commission's words, there is no legal entitlement to have the next working day off work; Good Friday is not a public holiday (Workplace Relations Commission)
- S.I. No. 580 of 2012, European Communities (Late Payment in Commercial Transactions) Regulations 2012, as made: regulation 2(1), relevant payment date; regulation 5(1), the ECB main refinancing rate plus 8 percentage points. Amended by S.I. No. 74 of 2013, S.I. No. 196 of 2014 and S.I. No. 281 of 2016 (Irish Statute Book)
- S.I. No. 74 of 2013, European Communities (Late Payment in Commercial Transactions) (Amendment) Regulations 2013, regulation 2: regulation 4 substituted; 4(2), interest for the period beginning on the day after the relevant payment date (Irish Statute Book)
- S.I. No. 196 of 2014, European Communities (Late Payment in Commercial Transactions) (Amendment) Regulations 2014, regulation 2: relevant payment date, 30 calendar days after the later of receipt of the invoice or delivery, or after an acceptance or verification procedure; regulation 5(1) now subject to paragraph (3); regulation 5(3), between undertakings the parties may vary the interest provided it is not grossly unfair to the creditor (Irish Statute Book)
- S.I. No. 281 of 2016, European Communities (Late Payment in Commercial Transactions) (Amendment) Regulations 2016, regulation 3: the definition of relevant payment date in regulation 2(1) amended; paragraph (a) substituted: between undertakings a date or period for payment that exceeds 60 calendar days must be expressly agreed in the contract and not be grossly unfair to the supplier (Irish Statute Book)
- Legislation Directory, statutory instruments of 2012, as read on 2026-10-13 (updated to 17 September 2026): S.I. No. 580 of 2012 is affected in its text by S.I. No. 74 of 2013 (regulation 4 substituted), S.I. No. 196 of 2014 (regulations 2(1), 4 and 5 amended) and S.I. No. 281 of 2016 (regulation 2(1) amended), and by no later amending instrument (Irish Statute Book (Legislation Directory))
Checked October 13, 2026. All sources
How September 2027 is shaped
The headline count answers how many working days September 2027 contains. It does not answer where they sit, and for anything measured in consecutive days rather than cumulative days that second question is the binding one. What follows is derived entirely from the Irish holiday calendar and a working week that treats Saturday and Sunday as the weekend, with no assumption about how any particular obligation behaves.
The month that closes the third quarter
September runs 30 days and closes Q3, so its last working day is also the quarter's. It shares its weekday alignment with December in every year, which means the September and December calendars are the same shape and differ only in length and in what closes them. That pairing is worth knowing when a plan is copied between the two quarters.
In September 2027 that comes to 22 working days across 30 calendar days, against 21 in August 2027 and 20 in October 2027.
A midweek start
September 2027 begins in the middle of a working week. Two of that week's working days belong to the month before and the rest to this one, so the first row of any weekly report covering September is a partial row. Midweek starts are the ones that most often produce an apparent dip in week-one output: the week is short, not the team.
The opening stretch runs from Wednesday, September 1 to September 3, three working days before the first break. September 2027 carries 22 working days in total, so that opening block is 14% of the month's working capacity.
Five working stretches
September splits into five working stretches. That is the ordinary shape of a month whose only interruptions are its weekends, and it means the month's internal boundaries are all predictable a year in advance: nothing here depends on a holiday date moving.
The working days of September 2027 arrive in stretches of 3, 5, 5, 5, and 4 days. The longest unbroken stretch runs five days, from September 6 to September 10. A task needing more consecutive working days than that cannot be completed inside a single stretch, whatever the month's total looks like.
The month is back-loaded. It opens with three consecutive days and closes with four, so the room is at the end rather than the start. That is the safer of the two imbalances, because a slip has somewhere to go, but it also makes the opening week a poor sample of the month.
Two weekdays occur five times
Thirty days is four seven-day cycles plus two, so a 30-day month has exactly two weekdays occurring five times and five occurring four times. Here they are Wednesday and Thursday. The pair is always consecutive, because the surplus days are the first two of the month repeated at its end.
All of them are working days here, so the surplus lands entirely on the working week: Wednesday and Thursday each occur 5 times. Had the surplus fallen on the weekend instead, the same month would carry 20 working days rather than 22.
A month with no closures, and a long one
September 2027 contains no Irish holiday on any date, working or otherwise. A month with no closure loses working days only to weekends, so its count is set entirely by the weekday it opens on and its length, and here both work in the month's favour: 22 working days across 30 calendar days.
Months at this end of the range are the ones worth reserving for work that needs consecutive days rather than cumulative days. The constraint that usually breaks a long run, a closure landing mid-week, is absent, so the month's structure is entirely weekend-driven and repeats on a seven-day cycle.
The closures on either side of the month
Nothing closes inside September 2027 under the Irish calendar, so the useful question is what sits on either side of it. Adjacent closures matter to a monthly plan because deadlines that fall near a month boundary are usually satisfied on the other side of it.
Looking outside the month, the last was August Bank Holiday on August 2, 2027, 30 calendar days before September began and the next is October Bank Holiday on October 25, 2027, 25 calendar days after it ends.
Across the whole of 2027 the Irish calendar puts ten closures on working days, of which none falls in September. That ratio, rather than the raw count, is what tells you whether a month is carrying more than its share of the year's downtime.
One working day short of the week
September 2027 closes on the fourth working day of its final week, one day short of a full week. The remaining working day of that week belongs to the next month, so the last calendar week of September is split across two reporting periods. Weekly and monthly figures for that week will not agree, and the difference is one working day.
The last working day of September 2027 is Thursday, September 30. Counting back from there, the third-to-last is Tuesday, September 28, two calendar days before the month closes.
The quarter closes here
September closes Q3, so the quarter's last working day and this month's last working day are the same date. Everything the quarter has deferred arrives inside these 22 working days, and there is no further month in the period to move it into.
Across the whole quarter there are 65 working days, of which 22 fall in September. The other two months carry July 2027 with 22 and August 2027 with 21. It sits between the other two, which makes it the month where a quarterly plan is least likely to be thrown off by the calendar alone.
The week's first working day is the scarcest
The first working day of the week is the one September gives least often. Anything anchored to the start of the working week (a weekly kickoff, a Monday-morning cutoff, a start-of-week batch) fires fewer times this month than the calendar count suggests, because a closure has taken one of them out.
Counted as worked rather than as occurring, September 2027 gives Monday 4, Tuesday 4, Wednesday 5, Thursday 5, and Friday 4. A weekly commitment pinned to a particular weekday fires that many times in the month, which is the number a rota needs and not the one the calendar shows.
Toward the long end of the year
September sits among the longer working months of 2027 under the Irish calendar. Where a month falls in that ranking is decided by two independent things, its calendar length and how many closures land on its working days, so a month can move several places between adjacent years without its length changing at all.
2027 carries 251 working days in total under the Irish calendar. The longest month of the year is April 2027 with 22 and the shortest is February 2027 with 19, a spread of 3. September ranks 3rd of the twelve with 22.
Inside the year's longest clear run
September 2027 sits inside the longest stretch of 2027 with no Irish closure in it. Where a month falls relative to its country's closure clusters changes what the same working-day count is worth: an uninterrupted month inside a long clear run behaves differently from one of equal length wedged between two closures.
Across 2027 the Irish closures fall 5 in Q1, 2 in Q2, 1 in Q3, and 2 in Q4. Every holiday in the Irish data for 2027 falls on a working day, so the country's holiday count and its working-day loss are the same number this year, which is not usually the case.
The longest uninterrupted run in the 2027 calendar sits between August 2, 2027 and October 25, 2027, 84 calendar days with no Irish closure in between. Stretches like that are where multi-week work belongs, and they move from year to year whenever a movable holiday does.
Where the month sits in the year's closure pattern
Closures are not spread evenly across a calendar year. They cluster around fixed anniversaries and around whichever lunar or movable feasts a jurisdiction observes, so two adjacent months can carry very different loads, and the Irish calendar is no exception.
2027 opens its Irish closures with New Year's Day on January 1, 2027 and ends them with St Stephen's Day (additional) on December 27, 2027. The densest month of the year is March 2027 with three closures on working days.
The same count as last year
September 2027 and September 2026 carry the same number of working days, 22 in each. An unchanged total does not mean an unchanged month: the working days sit on different dates and break into different stretches, so a schedule copied forward date by date will not line up even though the capacity has not moved.
September opens 2026 on a Tuesday, 2027 on a Wednesday, and 2028 on a Friday. That movement, one weekday in a common year and two after a leap day, is what makes the three counts differ. The number of closures on working days is the same in both years, so the whole of any difference comes from weekday alignment. Looking ahead, September 2028 carries 21 working days.
Where the month's anchor dates fall
Two of the common monthly anchor dates in September 2027 land outside the working week or on a closure. The table below resolves each one against the Irish calendar, together with the first working day on or after it.
| Date | Weekday | Status under the Irish calendar | First working day on or after |
|---|---|---|---|
| September 1 | Wednesday | Working day | September 1 |
| September 5 | Sunday | Weekend | September 6, 2027 |
| September 10 | Friday | Working day | September 10 |
| September 15 | Wednesday | Working day | September 15 |
| September 20 | Monday | Working day | September 20 |
| September 25 | Saturday | Weekend | September 27, 2027 |
| September 30 | Thursday | Working day | September 30 |
The final column is arithmetic, not a legal conclusion. Whether an obligation actually moves when its date is not a working day depends on the instrument that sets it, and this site does not assume a shift rule for any jurisdiction. Where a rule is known it is stated in the holiday data methodology and on the country page it applies to.
Net terms dated in September 2027
An invoice dated the 1st of September on calendar-day Net 30 terms comes due on October 1, 2027, a working day under the Irish calendar. Terms counted in calendar days move independently of the working week, so the same term written on two consecutive months can settle cleanly in one and roll across a closure in the other.
| Invoice date | Net 30, calendar days | Net 60, calendar days |
|---|---|---|
| Dated September 1 | October 1, 2027 | October 31, 2027 (rolls to November 1, 2027) |
| Dated September 15 | October 15, 2027 | November 14, 2027 (rolls to November 15, 2027) |
| Dated September 30 | October 30, 2027 (rolls to November 1, 2027) | November 29, 2027 |
Net 30 and Net 60 are commercial conventions rather than statutory periods, and both are counted here in calendar days, which is how they are almost always written. Where a contract counts in working days instead, use the between-dates calculator with the Ireland calendar selected, because the two produce different dates whenever a closure falls inside the term.
Sources and verification
Official source: Workplace Relations Commission (workplacerelations.ie) (opens in a new tab)
Cross-checked against this source on October 7, 2026.
For informational purposes only
This calculator provides general estimates based on business day counting rules. It does not constitute legal advice. Deadlines in legal, regulatory, or contractual matters may be subject to jurisdiction-specific rules, court orders, or statutory exceptions. Always verify critical deadlines with a qualified professional.
Frequently Asked Questions
How many business days are in September 2027 under the Irish holiday calendar?
Which Ireland holidays affect September 2027?
Why is St Brigid's Day included from 2023 onward?
What happens when an Irish public holiday falls on a weekend?
Why does the business-day count vary year to year?
When is the last working day of September 2027?
How many working days in a row does September 2027 offer?
Sources for these rules
- S.I. No. 50 of 2022, Organisation of Working Time (Covid-19 Commemoration) Regulations 2022, regulations 4 and 5: the first Monday in February from 2023, or 1 February in a year when it falls on a Friday, is prescribed for the purposes of paragraph 1 of the Second Schedule to the Act of 1997; explanatory note: in celebration of Imbolc/St. Brigid's day, the first such public holiday being Monday 6th February 2023 (Irish Statute Book)
- Public Holidays: the ten public holidays and their 2026 dates; the benefit for a public holiday is a paid day off on that day, a paid day off within a month, an additional day of annual leave or an additional day's pay; where the holiday falls on a Saturday or Sunday, in the Commission's words, there is no legal entitlement to have the next working day off work; Good Friday is not a public holiday (Workplace Relations Commission)
- Circular 5/1984, Public and Privilege Holidays (Minister for the Public Service), paragraph 2: the public holidays to be granted to civil servants, Good Friday among them; paragraph 3: when a public holiday falls on a Sunday, Government offices will be closed on the following day; paragraph 4: when it falls on a Saturday, a day off on the following Monday (for Christmas Day, Tuesday 28 December; for New Year's Day, 31 December or 3 January as each Department designates) may be granted (circulars.gov.ie (Government of Ireland))
- Bank Holidays - Republic of Ireland 2025-2027: Good Friday 18 April 2025, 3 April 2026 and 26 March 2027; Christmas bank holidays 25, 26 and 29 December 2025, 25, 28 and 29 December 2026, and 27, 28 and 29 December 2027 (Banking & Payments Federation Ireland)
- Bank Holidays - Republic of Ireland 2020-2022: for Saturday holidays, bank holidays on Monday 28 and Tuesday 29 December 2020 and on Monday 3 January 2022 (New Year's Day) (Banking & Payments Federation Ireland (archived copy))
- Public and Bank Holiday List 2026: Good Friday 3 April, and Monday 28 December (in lieu of Saturday 26 December) for St Stephen's Day (Department of Justice, Home Affairs and Migration)
Checked October 13, 2026. All sources