The Form 11 (self-assessed income tax) deadline is 31 October 2026. ROS filers who pay preliminary tax on time typically get until mid-November.
For self-assessed taxpayers, 31 October is the busiest date in the Irish tax calendar. Three things are due on the same day:
Taxpayers who file via Revenue Online Service (ROS) and also paid their 2026 preliminary tax through ROS by 31 October qualify for an extended deadline — typically announced by Revenue in mid-October. In recent years this has been approximately 12–14 November.
Important: the extension applies to both the filing AND the balance payment. However, to qualify, you must have paid your preliminary tax via ROS by 31 October — paying by cheque or bank transfer does not qualify even if paid on time.
Preliminary tax is an estimate of your 2026 income tax, paid in advance before your 2026 return is filed. To avoid interest, it must be the higher of:
Most accountants recommend paying 100% of the prior year's liability — it avoids any risk of interest and eliminates the need to estimate 2026 income before the year ends.
| When you file | Surcharge | Max surcharge |
|---|---|---|
| On time (by 31 Oct or ROS extension) | None | — |
| 1 Nov to 31 Dec 2026 (≤2 months late) | 10% of tax owed | €63,493 |
| From 1 Jan 2027 (>2 months late) | 20% of tax owed | €63,493 |
In addition to the surcharge, daily interest of 0.0219% applies to any unpaid tax from the due date.
D’Emilia Accounting files Form 11, CT1, and VAT returns for individuals and businesses in Ireland. Never worry about a late filing surcharge again.
The statutory deadline for the 2025 self-assessed income tax return (Form 11) is 31 October 2026. Taxpayers filing via ROS who also paid their 2026 preliminary tax via ROS on time typically receive an extended deadline of approximately 12 November 2026 — the exact date is announced by Revenue in October.
Anyone who is self-employed (sole trader, partnership), a company director who is a proprietary director, has investment income, rental income, foreign income, or any income not fully taxed at source through PAYE. You must also file if Revenue asks you to, even if you have PAYE income.
Preliminary tax is an advance payment of your 2026 income tax, due by 31 October 2026. It must be at least 90% of your 2026 final liability, or 100% of your 2025 liability. If you underpay preliminary tax, interest accrues on the shortfall.
Revenue offers taxpayers who file via their Online Services (ROS) an extension — typically about two weeks beyond 31 October. You must have paid your 2026 preliminary tax via ROS on time to qualify. Failure to pay preliminary tax means the extended deadline does not apply to your balance payment.
File the return on time regardless. The late filing surcharge (10%/20%) applies to filing — not payment. Filing late and paying late means both a surcharge AND interest. Filing on time but paying late means only interest (0.0219%/day). Contact Revenue about a payment arrangement for the balance.
10% of the tax owed if filed up to 2 months after the deadline; 20% if filed more than 2 months late. The surcharge is capped at €63,493. It applies to the chargeable tax for the year, not just the balance due.
Disclaimer: General information only. Verify at revenue.ie. Not tax advice.
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