A guide to self-assessment

Pay and file system - how does it work?

By 31 October in a tax year, you must:

  • pay your preliminary tax for that year
  • file your self-assessment tax return for the previous tax year
  • and
  • pay any balance of tax due for the previous year.

For example, by 31 October 2024 you must:

  • pay your preliminary tax for 2024
  • file your 2023 self-assessment tax return
  • and
  • pay any Income Tax balance for 2023.

When you pay and file through the Revenue Online Service (ROS), the 31 October deadline is extended to mid-November. To avoid interest charges, please ensure you file by the correct due date.


The payment date for Capital Gains Tax (CGT) is different to the payment date for Income Tax.

You can amend any errors on your tax return through ROS. If you have filed a paper copy, please contact your Revenue Office to make any necessary amendments to your return.

You will have to pay a surcharge if you file your tax return after the deadline. Where a late return is filed:

  • within two months of the filing date a surcharge of 5% of your tax due, up to €12,695, is applied
  • or
  • over two months a surcharge of 10% of your tax due, up to €63,485, is applied.


A 10% surcharge may apply to your final liabiltiy if your Local Property Tax (LPT) obligations are not met. This surcharge may apply even if you pay and file on time for Income Tax.

Next: What forms do you need to complete?