Cohabitant inheritance tax calculator (Ireland 2026)

An unmarried partner or cohabitant in Ireland is treated as Group C for CAT purposes, with a threshold of just €20,000 for 2026. This calculator works out the tax on the excess at 33%, an important number given that cohabitants have no automatic inheritance right either.

Cohabitants in Ireland (unmarried partners who live together without a civil partnership) are not treated as spouses for CAT purposes. They fall under Group C with a 2026 threshold of €20,000, the same as a friend or distant relative. Any inheritance above that figure is taxed at 33%.

Two separate issues compound the problem. First, cohabitants have no automatic right to inherit under the intestacy rules in Section 67 of the Succession Act 1965, so a will is essential to give the cohabitant anything at all. Second, even with a will, the low Group C threshold means meaningful CAT on anything substantial, unless Dwelling House Exemption applies to the shared home.

How this calculator works

The calculator applies the 2026 Group C threshold of €20,000 and taxes the excess at 33%. Prior Group C receipts since 5 December 1991 are aggregated.

What to do with the number

If the inheritance includes the shared home and the cohabitant has lived there for three or more years, Dwelling House Exemption can eliminate CAT on the house entirely, which is often the single biggest element of a cohabitant's inheritance. Start with the Readiness Check to confirm DHE eligibility and the overall CAT position; if the estate is otherwise straightforward, upgrade to the Preparation Pack or Complete Bundle depending on which the Readiness Check recommends.

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.