Inheritance Tax When Second Parent Dies UK
Introduction
Understanding inheritance tax when the second parent dies in the UK is one of the most important financial challenges families face after bereavement. While most estates pass tax-free when the first parent dies, the situation changes significantly once both parents have gone, and with UK inheritance tax receipts hitting £8.2 billion in 2024/25, more families than ever are being drawn into the IHT net. Knowing how the rules work and what allowances are available can make a substantial difference to how much of an estate actually passes to the next generation.
How Inheritance Tax Works When the First Parent Dies
In most cases, inheritance tax (IHT) is not a concern when the first parent dies, provided they leave their estate to the surviving spouse or civil partner.
This is because of the spousal exemption: transfers between married couples and civil partners are completely free of inheritance tax, regardless of the estate’s value. So if one parent dies and leaves everything to the other, no IHT is due at that point.
This does not mean the estate escapes inheritance tax entirely. The liability is effectively deferred. When the second parent later dies, the combined value of all assets, property, savings, investments, pensions, and personal belongings is assessed together, and this is the point at which IHT is most likely to apply.
It is also worth noting that if the first parent left assets to people other than their spouse, for example, directly to children, those gifts may use up part of their nil-rate band, which affects what can be transferred later.
What Is the Nil-Rate Band and How Does It Transfer?
Every individual subject to UK inheritance tax has a nil-rate band (NRB), the threshold below which no IHT is charged. This is currently set at £325,000 and has been frozen at this level since April 2009. The chancellor confirmed in the 2025 Budget that it will remain frozen until at least April 2031.
When one spouse or civil partner dies and their nil-rate band is not fully used, as is typically the case when everything is left to the surviving spouse, the unused portion can be transferred to the second spouse’s estate. This is known as the Transferable Nil-Rate Band (TNRB).
Practically, this means that if the first parent left their entire estate to the surviving spouse, their nil-rate band was 100% unused. When the second parent dies, their estate can claim that unused allowance on top of their own, giving a combined threshold of £650,000 before IHT applies.
The TNRB is calculated as a percentage of the nil-rate band unused at the first death, not the cash amount. This is important because the NRB in force at the time of the second death applies. So even if the first parent died when the NRB was lower, the full current amount can be transferred as long as 100% was unused.
A formal claim must be made using HMRC form IHT402, submitted alongside the IHT400 after the second parent’s death. The claim must be made within 24 months of the end of the month in which the second parent died. It is not applied automatically; executors must actively claim it, and supporting documentation from the first death (will, grant of probate, estate details) will be required.
The Residence Nil-Rate Band: An Additional £175,000 Per Parent
Beyond the standard nil-rate band, families may also benefit from the Residence Nil-Rate Band (RNRB), an additional tax-free allowance introduced in April 2017. This is currently set at £175,000 per person and applies when a qualifying residential property is left to direct descendants, children, grandchildren, or stepchildren (but not nephews, nieces, siblings, or friends).
Like the standard NRB, any unused RNRB from the first parent’s estate can be transferred to the second. This means a married couple could potentially pass on a family home worth up to £350,000 free of inheritance tax, purely through the combined RNRB.
When both the standard nil-rate band and the residence nil-rate band are fully available—including transferred amounts from the first parent—the total combined IHT-free threshold for a couple can reach £1,000,000:
- Standard NRB: £325,000 × 2 = £650,000
- Residence NRB: £175,000 × 2 = £350,000
- Total: £1,000,000
However, the RNRB is subject to a taper: for estates with a net value exceeding £2 million, the allowance reduces by £1 for every £2 above that threshold. Estates above £2.35 million receive no RNRB at all.
How Is the IHT Bill Calculated When the Second Parent Dies?
When the second parent dies, HMRC assesses the full value of their estate, everything they owned at the time of death, including their share of any jointly held property.
IHT is charged at 40% on the value of the estate above the available threshold. Once the applicable nil-rate bands have been determined (including any transferred from the first parent), the calculation is straightforward: the portion of the estate above the combined threshold is taxed at 40%.
Example: Suppose the second parent dies with an estate worth £900,000, and the full combined NRB (£650,000) and RNRB (£350,000) are available. The estate would be below the £1,000,000 combined threshold, and no IHT would be due. However, if the estate were worth £1,200,000, the IHT liability would be 40% of £200,000, equating to an £80,000 tax bill.
IHT is generally due within six months of the end of the month in which the person died. Interest is charged on unpaid tax after that point, which can create significant pressure where most assets are tied up in property that takes time to sell.
What Happens If There Is No Will?
If either or both parents die without a valid will, the estate is distributed according to the rules of intestacy, which may not reflect the family’s wishes and can increase tax exposure.
Under intestacy rules, assets may be distributed in ways that fail to make use of the spousal exemption or optimise available nil-rate bands. This can result in a larger IHT liability than would have been the case with careful estate planning.
Creating a clear, up-to-date will is one of the most practical steps families can take to ensure their estate is structured as tax-efficiently as possible and that the transfer of assets is handled according to their intentions.
What Are the Upcoming Changes to Inheritance Tax That Families Should Know About?
The inheritance tax landscape is continuing to evolve. Families managing or planning estates should be aware of several significant changes announced in recent budgets:
Pension funds from April 2027: From April 2027, unspent pension funds will form part of a person’s estate for IHT purposes. This is a substantial shift of pension pots that were previously outside the IHT net and is expected to significantly increase the number of estates subject to inheritance tax in the coming years.
Agricultural and Business Property Relief from April 2026: Currently, qualifying agricultural and business assets can receive 100% relief from IHT. From April 2026, that full relief will only apply to the first £1 million of combined qualifying assets, with a 50% relief rate (equating to an effective 20% IHT rate) applying to assets above that threshold.
Frozen thresholds until 2031: The nil-rate band and residence nil-rate band are both frozen at current levels until at least April 2031. With property values continuing to rise, this means more estates will cross the IHT threshold over time.
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How Can Families Reduce the Inheritance Tax Liability?
While inheritance tax cannot always be avoided, there are legitimate and well-established strategies that can help reduce exposure:
Lifetime gifting: Gifts made more than seven years before death are generally exempt from IHT. This includes cash, property, and other assets. The seven-year rule applies, and taper relief is available for gifts made between three and seven years before death.
Annual gift exemption: Each person can give away up to £3,000 per year free of IHT, and unused allowances can be carried forward one year.
Charitable giving: Leaving at least 10% of the net estate to a qualifying charity reduces the IHT rate on the remainder from 40% to 36%.
Trusts: Structured correctly, trusts can be used to pass assets outside the estate, though the rules are complex and professional legal advice is essential.
Life insurance in trust: A life insurance policy written in trust can provide a lump sum to cover IHT liabilities without increasing the value of the estate, helping beneficiaries avoid the need to sell property to fund a tax bill.
Conclusion
Inheritance tax when the second parent dies in the UK can represent one of the largest financial events a family will experience. The good news is that the UK tax framework provides meaningful allowances, including the transferable nil-rate band and residence nil-rate band, that can allow couples to pass on up to £1 million completely free of IHT when structured correctly.
The key is preparation: keeping records from the first parent’s death, ensuring wills are in place and up to date, and seeking professional advice where the estate is complex. With the nil-rate bands frozen until 2031 and further changes on the horizon, proactive estate planning has never been more important.
