Preliminary Tax (Companies)
Advance Corporation Tax payment due one month before company year-end (specifically the 23rd of that month for ROS users). 90% of current year liability or 100% of prior year for small companies. Small companies pay once, 31 days before the end of the accounting period and no later than the 23rd of that month. The company pays either 90 per cent of its final liability for the current period or 100 per cent of the liability for the previous period.
Finn tracks your Ireland deadlines
AccountsOS tracks your tax and filing deadlines, keeps the books and handles invoicing for Ireland businesses, in plain English. Ask Finn about yours, no signup needed.
Who this applies to
- All Irish-resident companies with a CT liability over €200,000 prior year (otherwise 100% prior year is enough)
- New companies in their first accounting period are exempt
What to file
Preliminary tax payment via ROS: no form required, just the cash payment. Large companies, with a corporation tax liability of €200,000 or more in the previous period, can pay in two instalments if the period is longer than seven months. The first is due on the 23rd of the sixth month and is 50 per cent of the previous period's liability or 45 per cent of the current period's. The second is due on the 23rd of the eleventh month and brings the total to 90 per cent of the final tax for the current period. Where the period is under seven months, 90 per cent is paid in one instalment.
How to file
Pay via ROS using single debit instruction or RDI direct debit.
Payment due
23rd of penultimate month before year-end.
Penalties for missing this deadline
Daily interest at approximately 8% annualised on shortfall from due date until paid. No fixed-amount penalty. Interest on unpaid corporation tax runs at 0.0219% a day. It cannot be appealed and cannot be reduced once charged.
Filing checklist
- Estimate current year CT liability (90% threshold)
- Or use 100% of prior year CT (small company option)
- Pay via ROS by the 23rd
- Keep ROS receipt for CT1 reconciliation
- If the period is not listed in ROS, open a new period through MyEnquiries before paying, otherwise the payment can be applied to an earlier period
Documents you'll need
- Management accounts or profit forecast supporting the current-year estimate
- Last year's final corporation tax figure from the filed CT1
Common mistakes to avoid
- Paying the wrong amount and triggering interest
- Forgetting to pay because there is no return to file
- Using current year estimate when prior year would have sufficed (capital tied up)
- Paying the first instalment of a large company at 50 per cent of the current year instead of 50 per cent of the previous year or 45 per cent of the current year
Never miss a Ireland deadline
AccountsOS tracks every Revenue (Revenue Commissioners) and Companies Registration Office (CRO) deadline and reminds you weeks ahead.
Try Free