Inheritance Tax When Second Parent Dies: How UK Allowances Work

Last Updated: 08.07.2026

Inheritance tax when second parent dies usually depends on the value of the surviving parent’s estate, whether the first parent used any inheritance tax allowance, and whether a family home is being passed to children or other direct descendants.

In the UK, each person has a standard inheritance tax nil rate band of £325,000.

Where the first parent was married to, or in a civil partnership with, the second parent, any unused percentage of the first parent’s nil rate band can often be transferred to the second parent’s estate. This can increase the available basic inheritance tax threshold to as much as £650,000.

A further residence nil rate band of up to £175,000 may also apply where a qualifying home is left to direct descendants. If both parents’ residence allowances are available, this can potentially add another £350,000.

In the right circumstances, a married couple or civil partners may pass on up to £1 million before inheritance tax is due.

Key Takeaways:

• Inheritance tax after both parents die is not automatically charged on the whole estate. It is only usually due on the value above the available inheritance tax allowances and reliefs.
• The standard nil rate band is £325,000 per person, and the residence nil rate band is currently up to £175,000 where the conditions are met.
• Unused inheritance tax allowances can normally transfer only between spouses and civil partners, not between unmarried partners.
• The full £1 million inheritance tax allowance is not automatic. It generally depends on marriage or civil partnership, unused allowances, a qualifying home, direct descendants, and the value of the estate.
• For estates worth more than £2 million, the residence nil rate band is gradually reduced by £1 for every £2 above the taper threshold.

What Does “Inheritance Tax When Second Parent Dies” Mean?

Inheritance tax when second parent dies refers to the tax position after the surviving parent passes away and their estate is passed to beneficiaries, often children.

This is usually the point where inheritance tax becomes more relevant for families because assets from both parents may have ended up in the surviving parent’s estate.

When the first parent dies, assets often pass to the surviving spouse or civil partner. Transfers between spouses and civil partners are generally exempt from inheritance tax, so little or no inheritance tax may be due at the first death.

The second death is different because the estate may then pass to children, grandchildren or other beneficiaries rather than to a spouse.

This is why the estate of the second parent often needs a careful inheritance tax calculation. Executors or personal representatives may need to check the second parent’s own allowance, any unused allowance from the first parent, and whether the family home qualifies for the residence nil rate band.

Why the Second Death Is Often When IHT Becomes Relevant?

The second death often creates the main inheritance tax issue because the surviving parent may own the family home, savings, investments, pensions, personal possessions and other assets by that stage.

If the first parent left everything to the surviving spouse or civil partner, their nil rate band may have been unused.

That unused percentage can often be claimed against the second parent’s estate. However, the claim must be supported by information about the first death, including how the estate passed and whether any allowance was used.

This means the question is not simply “how much did the second parent leave?” The more accurate question is: what allowances, exemptions and reliefs are available against the second parent’s estate?

How the First Parent’s Unused Allowance May Transfer?

The transferable nil rate band allows the unused percentage of the first spouse or civil partner’s basic inheritance tax threshold to be transferred to the surviving spouse or civil partner’s estate.

For example, if the first parent left everything to the surviving parent, the first parent may not have used any of their £325,000 nil rate band. In that case, the second parent’s estate may be able to claim a 100% uplift, giving a basic nil rate band of £650,000.

HMRC form IHT402 is used with IHT400 to claim the transfer of an unused nil rate band from a deceased spouse or civil partner.

How UK Inheritance Tax Allowances Work After Both Parents Die?

UK inheritance tax allowances after both parents die can include the nil rate band, transferable nil rate band, residence nil rate band and transferable residence nil rate band. These allowances work together, but each has its own conditions.

The nil rate band applies to all individuals. The residence nil rate band is more specific because it relates to a qualifying residence that is inherited by direct descendants.

The transferable versions of these allowances are mainly relevant where the parents were married or in a civil partnership.

This is why two families with similar property values may have different inheritance tax outcomes. The final position depends on the family structure, estate value, property ownership, wills, previous gifts and available records from the first parent’s death.

The £325,000 Nil Rate Band

The nil rate band is the standard inheritance tax allowance available to an individual. It currently allows up to £325,000 of an estate to be taxed at 0% before inheritance tax is charged on the excess.

If an estate is worth less than the available nil rate band, inheritance tax may not be due. If the estate is worth more, inheritance tax is usually charged at 40% on the taxable amount, subject to exemptions, reliefs and other rules.

For a second parent’s estate, the nil rate band calculation should include whether any unused allowance from the first parent can be transferred.

The Transferable Nil Rate Band

The transferable nil rate band can increase the surviving parent’s available basic inheritance tax allowance. It applies where the first spouse or civil partner did not use all of their own nil rate band.

The transfer is based on the unused percentage, not simply the cash amount left over at the first death. This matters because the allowance may be claimed against the threshold in force when the second parent dies.

For many families, this is the allowance that explains why the inheritance tax threshold for married couples can be much higher than for a single person.

The £175,000 Residence Nil Rate Band

The residence nil rate band is an additional inheritance tax allowance that may apply when a person leaves a qualifying home to direct descendants, such as children or grandchildren.

The current residence nil rate band is up to £175,000. It can sit on top of the standard nil rate band, meaning an individual may have up to £500,000 in combined allowances if the conditions are met.

However, this allowance is not available in every estate. It usually requires a qualifying residential interest and a qualifying beneficiary.

The Transferable Residence Nil Rate Band

Where the first parent did not use their residence nil rate band, the unused percentage may be transferable to the second parent’s estate if the conditions are met.

This can be especially important where the family home passes to children after the second parent dies. If both residence nil rate bands are available in full, this may add up to £350,000 in additional inheritance tax allowance.

The transferable residence nil rate band should be considered separately from the transferable nil rate band. Executors should not assume one automatically means the other applies.

When Can Children Use Both Parents’ Inheritance Tax Allowances?

Children may benefit from both parents’ inheritance tax allowances when the parents were married or civil partners, the first parent left unused allowances, and the second parent’s estate meets the relevant conditions.

This is common where the first parent left everything to the surviving parent and the surviving parent later leaves the estate to the children.

In that situation, the second parent’s estate may be able to claim both parents’ nil rate bands and, where a qualifying home is involved, both residence nil rate bands.

The rules are different for unmarried parents. Even long-term cohabiting couples do not automatically receive the same inheritance tax transfer rules as spouses or civil partners.

Married Couples and Civil Partners

Married couples and civil partners receive important inheritance tax advantages. Assets passing between them are generally exempt from inheritance tax, and unused allowances can often be transferred to the survivor’s estate.

This is why inheritance tax after both parents die often focuses on whether the first parent’s allowances were used.

If they were not used, the surviving parent’s estate may have a much larger inheritance tax threshold.

The transferable nil rate band and transferable residence nil rate band can significantly reduce or remove the inheritance tax liability for some family estates.

Why Unmarried Couples Are Treated Differently?

Unmarried couples do not have the same inheritance tax treatment as married couples or civil partners. A surviving unmarried partner cannot usually inherit unused nil rate band allowances in the same way.

This means that children of unmarried parents may not be able to use both parents’ inheritance tax allowances through the transferable allowance rules. Each parent’s estate is considered separately, and inheritance tax may arise earlier.

This distinction is important because many families assume long-term cohabitation has the same tax effect as marriage or civil partnership. For inheritance tax purposes, it does not.

What Counts as a Direct Descendant?

For the residence nil rate band, direct descendants usually include children, grandchildren and other lineal descendants. It can also include some stepchildren, adopted children and foster children, depending on the circumstances.

The residence nil rate band is designed to help families pass on a home to direct descendants. It is not usually available where the property is left to siblings, nieces, nephews, friends or unrelated beneficiaries.

Because the rules can be technical, estates involving blended families, trusts or unusual will structures may need professional advice.

How the £1 Million Inheritance Tax Allowance Can Apply?

The commonly mentioned £1 million inheritance tax allowance can apply where a married couple or civil partners leave a qualifying estate to direct descendants and all available allowances are unused and transferable.

The figure is made up of two £325,000 nil rate bands and two £175,000 residence nil rate bands. Together, these can total £1 million. However, this is not a separate allowance and it is not guaranteed for every family.

The estate must meet the relevant conditions. The family home must qualify, it must pass to direct descendants, and the residence nil rate band may be reduced if the estate is worth more than £2 million.

Example Allowance Breakdown

A full allowance position may look like this:

This table shows why families often ask about inheritance tax when second parent dies. The second death may be when all the available allowances are brought together and applied against the estate.

When the Full £1 Million May Not Be Available?

The full £1 million inheritance tax allowance may not be available if the parents were not married or civil partners, if the first parent used some of their allowance, or if the estate does not include a qualifying home passing to direct descendants.

It may also be reduced where the estate is valued above £2 million because the residence nil rate band begins to taper away. Trusts, lifetime gifts, business assets and overseas property can also affect the calculation.

For this reason, the £1 million figure should be treated as a possible maximum, not a guaranteed inheritance tax threshold.

Estates Over £2 Million and Residence Nil Rate Band Tapering

For estates worth more than £2 million, the residence nil rate band is gradually reduced. GOV.UK explains that the residence nil rate band reduces by £1 for every £2 that the estate is worth above the £2 million taper threshold.

This can make a major difference for higher-value estates, especially where property prices have increased over time. Even if a home is left to children, the available residence nil rate band may be reduced or removed entirely.

Families with estates near or above £2 million should be careful when estimating inheritance tax, as the taper can reduce the expected allowance.

Confirmed Facts About UK Inheritance Tax After the Second Parent Dies

The main confirmed inheritance tax facts are that the nil rate band is £325,000, the residence nil rate band is up to £175,000, and unused allowances can often transfer between spouses and civil partners.

Inheritance tax is normally calculated on the estate after debts, exemptions and reliefs are considered. The tax position can change depending on gifts, trusts, property ownership and who inherits the estate.

For second parent estates, the most important practical point is record-keeping. Executors may need information from the first parent’s death to claim transferable allowances correctly.

Current HMRC Thresholds

The current standard nil rate band is £325,000. The residence nil rate band is up to £175,000 where a qualifying residence passes to direct descendants.

The available threshold for a second parent’s estate may be higher if the first parent’s unused allowance can be transferred. This can potentially create a combined basic threshold of £650,000 before the residence nil rate band is considered.

Where both residence nil rate bands apply in full, the available allowances can potentially reach £1 million.

Transfer Rules for Spouses and Civil Partners

Transfer rules apply where the first spouse or civil partner did not use all of their inheritance tax allowance. The unused percentage can be claimed by the estate of the second spouse or civil partner.

These rules are important because the first parent’s estate may have paid no inheritance tax if everything passed to the surviving spouse or civil partner. In that case, the first parent’s nil rate band may remain fully unused.

The second parent’s executors must usually make the relevant claim rather than assuming HMRC will apply the transfer automatically.

Relevant HMRC Forms, Including IHT400, IHT402 and IHT435

Inheritance tax forms depend on the estate and the type of claim being made. HMRC states that IHT402 is used with IHT400 to claim the transfer of unused nil rate band from a deceased spouse or civil partner.

Where the residence nil rate band or transferable residence nil rate band is relevant, further inheritance tax forms may be needed. Executors should check the current HMRC requirements before submitting an estate return.

Using the wrong form or missing a transferable allowance can affect the inheritance tax calculation and delay estate administration.

Proposed or Upcoming Changes Families Should Know About

Families should be aware that inheritance tax rules can change. Thresholds, pensions, reliefs and estate planning rules may be updated by future Budgets or legislation.

The nil rate band and residence nil rate band have been frozen for several years, which can bring more estates into inheritance tax as property and asset values rise.

GOV.UK lists the current residence nil rate band at £175,000 for the period shown in its official thresholds guidance.

Because inheritance tax is a YMYL topic affecting money and family wealth, readers should always check official guidance or seek professional advice before making estate planning decisions.

Frozen Inheritance Tax Thresholds

Frozen thresholds mean the allowance amounts stay the same while asset values may increase. For families whose main wealth is in a home, this can make inheritance tax more likely over time.

This is especially relevant in areas where property values have risen significantly. A family may not consider itself wealthy but may still have an estate that approaches or exceeds the inheritance tax thresholds.

For second parent estates, the impact can be greater because the surviving parent may hold most of the family’s combined assets.

Pension and Estate Planning Changes From April 2027, Where Relevant

The UK government has announced changes that are expected to bring unused pension funds and death benefits into inheritance tax calculations from April 2027. GOV.UK has published inheritance tax threshold material connected to these future rules.

This may affect families where the second parent dies with significant unused pension funds. It may also change how some families think about retirement income, estate planning and beneficiary nominations.

The detail should be checked carefully nearer the time because pension inheritance tax rules can be complex and may depend on the type of pension and estate structure.

Inheritance Tax Allowances 

This comparison shows that inheritance tax after both parents die is not based on one single allowance. It is a layered calculation involving the estate value, family relationship, property position and available transfer claims.

Conclusion

Inheritance tax when second parent dies can be more favourable than many families expect, but only if the correct UK allowances are available and claimed properly.

The second parent’s estate may be able to use their own nil rate band, the first parent’s unused nil rate band, the residence nil rate band and the transferable residence nil rate band.

In suitable cases, married couples and civil partners may pass on up to £1 million before inheritance tax is due.

However, this depends on the estate structure, whether a qualifying home passes to direct descendants, and whether the residence nil rate band is reduced by the £2 million taper.

The safest approach is to calculate the estate carefully, review the first parent’s records, check HMRC guidance and take professional advice where the estate includes property, pensions, trusts, gifts or high-value assets.

FAQs

Can both parents’ inheritance tax allowances be used after the second death?

Yes, both parents’ inheritance tax allowances may be used after the second death if the parents were married or civil partners and the first parent left unused allowances. The second parent’s estate may be able to claim the transferable nil rate band and, where the conditions are met, the transferable residence nil rate band.

What is the inheritance tax threshold for married couples in the UK?

For married couples and civil partners, the combined basic nil rate band can be up to £650,000 if the first person did not use any of their £325,000 allowance. If the residence nil rate band also applies in full for both parents, the total potential allowance can reach £1 million.

Does the family home always get the residence nil rate band?

No, the family home does not always get the residence nil rate band. The property must usually be a qualifying residence and must pass to direct descendants, such as children or grandchildren. The allowance may also be reduced if the total estate is worth more than £2 million.

What happens if the estate is worth more than £2 million?

If the estate is worth more than £2 million, the residence nil rate band is tapered. It reduces by £1 for every £2 above the £2 million threshold, which can reduce or remove the additional residence allowance.

Which HMRC forms are needed to claim transferable allowances?

HMRC states that IHT402 is used with IHT400 to claim the transfer of unused nil rate band from a deceased spouse or civil partner. Other forms may be needed where the residence nil rate band or transferable residence nil rate band is being claimed.

Do unmarried parents get the same inheritance tax allowance?

No, unmarried parents do not usually receive the same transferable inheritance tax allowance treatment as married couples or civil partners. Each estate is usually assessed separately, and unused allowances do not transfer in the same way.

Is inheritance tax paid before or after probate?

Inheritance tax is often paid before probate is granted, although some tax may be payable by instalments in certain cases, such as where property is involved. Executors should check HMRC rules and deadlines before applying for probate.

Editorial Note

This article has been prepared for general information purposes only and is based on current UK inheritance tax guidance available at the time of writing.

Inheritance tax rules can change, and the correct position may depend on the estate value, marital or civil partnership status, property ownership, wills, lifetime gifts, pensions, trusts and available HMRC records.

Readers should check the latest GOV.UK and HMRC guidance or seek advice from a qualified tax, legal or probate professional before making decisions about inheritance tax or estate planning.

How This Article Was Edited?

The article was edited to follow a clearer, reader-first structure. The introduction, real-life example, executor guidance section and misinformation section were removed as requested.

The Key Takeaways section was moved directly after the Quick Answer so readers can understand the main inheritance tax points quickly.

Each heading was kept medium in length, with the main information placed directly under the relevant heading. The content also uses the primary keyword “inheritance tax when second parent dies” and related terms naturally throughout the article, without keyword stuffing.

Source Links

GOV.UK — Inheritance Tax thresholds and interest rates
https://www.gov.uk/government/publications/rates-and-allowances-inheritance-tax-thresholds-and-interest-rates/inheritance-tax-thresholds-and-interest-rates

GOV.UK — Transferring unused basic threshold for Inheritance Tax
https://www.gov.uk/guidance/transferring-unused-basic-threshold-for-inheritance-tax

GOV.UK — IHT402: Claim to transfer unused nil rate band
https://www.gov.uk/government/publications/inheritance-tax-claim-to-transfer-unused-nil-rate-band-iht402

GOV.UK — Inheritance Tax residence nil rate band
https://www.gov.uk/guidance/inheritance-tax-residence-nil-rate-band

GOV.UK — Technical note: Inheritance Tax on pensions
https://www.gov.uk/government/publications/inheritance-tax-on-pensions-technical-note/technical-note-inheritance-tax-on-pensions