Unused Nil Rate Band

[Wugan warrior]

This is my first post on this site so apologies if this question has been asked many times before.
My father died in 1988, when the IHT threshold was 110,000, leaving 65,000. My mother died last week. What is the cumulated NRB.

[maths]

If your father left his estate to his wife then on her death her estate is entitled to twice the current nil rate band ie £650,000 in total,

[pqtaxation]

...My mother died last week. What is the cumulated NRB?

My condolences on your mother’s recent death.

To expand on maths’ comment, even if your father did not leave any of his estate to your mother there is still a partial NRB that is transferable.

Presumably the value of your mother’s estate that is assessable to IHT is more than the the threshold (NRB) of £325k.

If none of your father’s estate valued at £65k passed to your mother (or other exempt beneficiary) and so all passed to non-exempt beneficiaries then (110-65)/110 = 40.9% of 325k = £133k is transferrable which when added to her own NRB of £325k gives about a £458k threshold.

More generally and algebraically, if T is value of your father’s estate passed to your mother, the transferrable NRB is (T +110-65)/110% of current NRB, £325k. Hence:
If T=65, 100% NRB
If T=0, 40.9% NRB of £325k

[Wugan warrior]

Thank you both for a very quick and concise reply