Fiscal year
A fiscal year is the 12-month period your Irish business uses for accounting and tax reporting.
Published Friday 2 October 2026
Table of contents
Key takeaways
- A fiscal year is the 12-month period your business uses for accounting and tax reporting, and it doesn't have to match the calendar year.
- In Ireland, the income tax year for individuals is the calendar year, from 1 January to 31 December.
- Companies can set their own financial year end and register or change it with the Companies Registration Office.
- The 2025 self-assessment return is due by 31 October 2026 on paper, or 18 November 2026 when you file and pay online.
What is a fiscal year?
A fiscal year is the 12-month period your business uses for accounting and tax reporting. It doesn't have to match the calendar year, so you can pick a financial year end that suits how you trade.
Fiscal years are usually named after the year they end in, so a year ending 31 December 2025 is often called FY25. You'll also see it called a financial year.
Fiscal year vs calendar year vs financial year
These terms overlap, but they aren't identical. Here's how each one is used in Ireland.
- Calendar year: the fixed 12 months from 1 January to 31 December
- Fiscal year: any 12-month accounting period a business chooses
- Financial year: another name for the fiscal year, used for a company's accounts
- Tax year: in Ireland, the calendar year from 1 January to 31 December, administered by Revenue
When does the fiscal year start and end in Ireland?
Ireland treats individuals and companies differently, so the answer depends on how your business is set up. Two rules matter most.
For individuals, Ireland's income tax year runs from 1 January to 31 December, in line with the calendar year. You can confirm the current dates through Revenue's self-assessment guidance.
A company sets its own financial year. Under the Companies Act 2014, a company's first financial year begins on incorporation and can run up to 18 months, while each later financial year must fall within seven days of 12 months. You set and change these dates with the Companies Registration Office (CRO), and you can register a limited company and choose your first year end at the same time.
Why your fiscal year matters
Your fiscal year shapes more than your accounts. It sets the rhythm for your reporting deadlines and financial planning across the year.
- Financial reporting: you file annual accounts and financial statements with the CRO.
- Tax compliance: corporation tax and VAT returns follow your financial year, while the self-assessment Pay and File deadline follows the tax year.
- Budget planning: you set targets and forecasts against a consistent 12-month window.
- Performance tracking: you compare results year on year across the same period.
- Seasonal alignment: you match your year end to your quietest trading period.
How to choose your fiscal year
Most companies can pick a year end that fits how money moves through the business. Weigh up a few factors before you decide.
- Revenue cycle: align your year end with the point your income settles down.
- Industry norms: match the reporting period that's common in your sector.
- Tax planning: time your year end to manage the cash you set aside for tax.
- Cash flow: choose a close date that lands when you hold more cash.
Your first company accounts can cover up to 18 months, and later ones cover 12 months. You can change your financial year end once every five years by filing an updated year end with the CRO. Your choice of cash or accrual accounting also affects how income and costs fall within that period.
Key dates in the Irish tax year
The Irish tax calendar runs on a Pay and File cycle, and missing it costs money. Here are the dates that matter for the 2025 tax year.
The tax year runs from 1 January to 31 December. Your 2025 income tax return (Form 11) is due by 31 October 2026 on paper, and this extends to 18 November 2026 if you both file and pay through the Revenue Online Service (ROS).
On that same Pay and File date you file your Form 11 for the previous year, pay any balance of tax due for that year, and pay preliminary tax for the current year, as Citizens Information explains. P60s were replaced in Ireland from 1 January 2019 by the Employment Detail Summary, which you access through Revenue's myAccount.
Key Pay and File dates for the 2025 tax year include:
- 1 January to 31 December 2025: the tax year you're reporting on
- 31 October 2026: paper filing and payment deadline for the Form 11
- 18 November 2026: extended deadline when you file and pay through ROS
Keeping on top of recording your transactions through the year makes hitting these dates far easier.
Simplify your year-end reporting with Xero
Xero keeps your books up to date with automatic bank feeds, so your numbers are ready when year-end and Pay and File come around. Real-time reports let you see your position at any point, without waiting for the year to close.
Start with a plan that fits your business and get one month free to see how much time you save on year-end reporting.
FAQs on fiscal year
Here are quick answers to common questions about the fiscal year in Ireland.
What's the difference between a fiscal year and the Irish tax year?
A fiscal year is a company's own 12-month accounting period, so it can end in any month. The Irish income tax year is fixed to the calendar year, which is why sole traders always report up to 31 December.
Can I change my company's financial year?
Yes, you can change your company's financial year end once every five years by filing the change with the CRO. The new end date then applies to your following accounts.
What happens if I miss the Pay and File deadline?
Revenue adds a surcharge to your tax bill and charges interest on any late payment, as set out in its guide to self-assessment. Filing on time protects your cash.
Do all businesses in Ireland use the same fiscal year?
No. Sole traders report on the calendar tax year, while companies set their own financial year end.
What are fiscal quarters?
Fiscal quarters are four roughly three-month periods within your fiscal year, often used for performance targets and VAT returns.
Related terms
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Disclaimer
This glossary is for small business owners. The definitions are written with their requirements in mind. More detailed definitions can be found in accounting textbooks or from an accounting professional. Xero does not provide accounting, tax, business or legal advice.