IT38 late filing penalty calculator (Ireland 2026)

If the IT38 is filed late, Revenue applies a 5% surcharge within the first two months and 10% thereafter, plus daily interest at roughly 0.0219% on any unpaid CAT from the filing deadline. This calculator works out the total for 2026.

If an IT38 return is filed after the 31 October deadline, Revenue applies a late-filing surcharge to the CAT owed. The surcharge is 5% of the CAT if the return is filed within two months of the deadline, and 10% if filed later. In either case, daily interest is also charged under Section 51 of the Capital Acquisitions Tax Consolidation Act 2003 on any unpaid CAT from the filing deadline to the actual payment date.

The daily interest rate published by Revenue has historically been 0.0219%, which works out at roughly 8% annualised. This calculator uses that rate as the default; check Revenue.ie for the current published rate if filing far into the future.

How this calculator works

The calculator takes the CAT owed and the number of days the filing is late. It applies the 5% or 10% surcharge (depending on whether the lateness is within two months or longer) and adds the daily interest on the unpaid CAT from the deadline to the filing date.

What to do with the number

The fastest way to reduce the total is to file the IT38 and pay the CAT immediately, which stops the daily interest. The surcharge is fixed by whether filing is within or outside the two-month window. If funds are not immediately available, a phased payment arrangement can be requested from Revenue, but the interest continues to run on any unpaid balance. The Complete Bundle includes the IT38 draft return, which cuts the preparation time to hours instead of days.

This calculator is a preparation tool using Irish tax rates and rules for 2026. It is not legal or tax advice. For complex estates, consult a solicitor or tax adviser. All values are estimates based on the information you provide.