Self-Assessment: ROS, Form 11 & Preliminary Tax

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What Is Self-Assessment?

Self-assessment is the system used by Revenue for individuals who have income that is not taxed through PAYE. This includes self-employed individuals, sole traders, partners in a partnership, and individuals with significant rental or investment income.

Updated for 2026 Revenue rates.

Who Must Register for Self-Assessment?

You must register for self-assessment if you:

Revenue Online Service (ROS)

ROS is Revenue's secure online portal for self-assessment taxpayers. Through ROS you can:

Registration for ROS requires a digital certificate or the Revenue myGovID mobile app. You can register at ros.ie.

Form 11

Form 11 is the annual tax return for self-assessment taxpayers. It captures:

The return must be filed online through ROS. The deadline for filing and payment is 31 October following the end of the tax year.

Preliminary Tax

You must make a preliminary tax payment by 31 October each year. This is an estimate of your tax liability for the current tax year. The minimum payment is:

If you underestimate your preliminary tax, you may be charged interest on the underpayment.

Tax Deadlines

Note: The October deadline applies whether you file paper returns or electronic returns. There is no extension to November for online filing for self-assessment.

Record Keeping

Self-employed individuals must keep accurate records of all income and expenses for at least 6 years. Revenue may request to see your records at any time. Recommended records include:

Penalties for Late Filing

Late filing of Form 11 incurs a surcharge of:

Interest is also charged at approximately 0.016% per day on late payments.

Who must file in 2026

You must register for self-assessment if you are self-employed (sole trader or partnership), a company director, or have significant non-PAYE income (rental income, investment income, foreign income). PAYE employees with modest additional income — for example, small rental profits or freelance earnings — may be able to declare it through the annual return in myAccount instead of full self-assessment; Revenue's guidance sets out the thresholds, and the 'Income tax return (Form 12)' route is simpler when it applies. If in doubt, register and file: the surcharge for late filing starts at 5% of the tax due, and interest runs on late payments.

The key dates

The annual cycle: preliminary tax for the current year is due by 31 October, together with the balance of the previous year's tax and your Form 11 (ROS filers who pay preliminary tax by direct debit get a short extension into mid-November). To avoid interest, your preliminary tax must be at least 90% of the current year's liability, or 100% of the previous year's liability (105% of the year before that if you pay by direct debit) — the 'safe harbour' rules. If you underestimate, interest is charged from the original due date, so it is better to overpay slightly and claim a refund than to underpay.

What goes on the Form 11

The Form 11 captures income from self-employment (with accounts), employment and pensions, rental income, investment and foreign income, chargeable gains, and the reliefs and allowances you are claiming (pension contributions, medical expenses, rent-a-room, capital allowances). If your business turnover is below the VAT threshold (€78,000 for services, €80,000 for goods in 2026), you do not register for VAT; above it, VAT becomes a quarterly obligation. Keep business records — Revenue requires 6 years of records for sole traders, and your accounts should distinguish business and personal expenses clearly.

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