Inheritance Tax When Second Parent Dies: What Families Need to Know in 2026

Families dealing with an estate after the death of their second parent may face Inheritance Tax (IHT), but the amount due can be very different from simply applying the standard £325,000 threshold.

Under current UK rules, a surviving married spouse or civil partner may inherit unused Inheritance Tax allowances from the first partner to die. In qualifying circumstances, this can mean that up to £1 million of an estate could potentially pass without Inheritance Tax when the second parent dies. However, the £1 million figure is not an automatic allowance for every family.

As of August 2026, the standard Inheritance Tax nil-rate band remains £325,000, while the residence nil-rate band remains £175,000. Both allowances can potentially be transferred between spouses or civil partners when they are unused.

With significant changes to the taxation of inherited pensions also due from 6 April 2027, understanding how Inheritance Tax works after the second parent dies is becoming increasingly important for UK families.

What Happens to Inheritance Tax When the Second Parent Dies?

When the second parent dies, the executors or personal representatives must calculate the value of that parent’s estate and establish which Inheritance Tax allowances are available.

The standard individual nil-rate band is £325,000. Ordinarily, IHT is charged at 40% on the taxable portion of an estate above the available threshold, although exemptions and reliefs can change the final calculation.

However, where the parents were married or in a civil partnership, the second parent’s estate may also benefit from unused allowances belonging to the first parent.

HMRC states that where none of the first spouse or civil partner’s basic threshold was used, the surviving partner’s estate can potentially receive a basic nil-rate band of up to £650,000.

There may then be an additional residence nil-rate band where a qualifying home is passed to direct descendants.

This is why the tax position after the second parent dies can be substantially different from the position applying to an unmarried individual.

Can Children Inherit £1 Million Tax-Free When the Second Parent Dies?

Potentially, but not automatically.

A commonly quoted figure is that a married couple can leave up to £1 million free of Inheritance Tax to their family.

The figure comes from combining four potential allowances:

Allowance	Maximum Potential Amount
Second parent’s nil-rate band	£325,000
Transferred nil-rate band from first parent	£325,000
Second parent’s residence nil-rate band	£175,000
Transferred residence nil-rate band	£175,000
Potential combined total	£1,000,000

HMRC confirms that the combined basic nil-rate band can reach £650,000 and the combined residence nil-rate band can reach £350,000.

Together, this creates a potential £1 million threshold.

But families should not assume that every estate automatically qualifies for the full amount.

Why the £1 Million Inheritance Tax Allowance Is Not Automatic

Several conditions affect whether the full £1 million can be used.

The residence nil-rate band is particularly important.

A person can receive the additional residence allowance when a qualifying home is passed to direct descendants, including children and grandchildren. HMRC’s definition can also include adopted children, foster children, stepchildren and certain other descendants.

Therefore, an estate containing £1 million of cash and investments but no qualifying residence would not necessarily receive the same allowances as an estate where a qualifying home passes to children.

The available residence nil-rate band can also be restricted by the value of the qualifying property.

What If the First Parent Left Everything to the Second Parent?

This is one of the most common situations.

Assets passing between qualifying spouses or civil partners are generally exempt from Inheritance Tax. A home can, for example, be passed to a husband, wife or civil partner without IHT being charged on that transfer, subject to the detailed residence-status rules.

If the first parent left their entire estate to their spouse or civil partner, their standard nil-rate band may have remained completely unused.

That unused percentage can potentially be transferred when the surviving spouse later dies.

Under today’s £325,000 nil-rate band, transferring 100% of the first spouse’s unused threshold could provide another £325,000, creating a combined basic allowance of £650,000.

The principle is based on the percentage of the first person’s nil-rate band that was unused, rather than simply transferring a fixed historic cash amount.

This matters where the first parent died many years earlier when the Inheritance Tax threshold was different.

Can the Residence Nil-Rate Band Transfer Too?

Yes.

Any unused residence nil-rate band can potentially transfer between married spouses or civil partners.

HMRC confirms that this can even apply where the first spouse died before the residence nil-rate band was introduced on 6 April 2017.

The surviving spouse’s estate must still meet the qualifying conditions when the second death occurs.

In particular, a qualifying residence normally needs to form part of the estate and be inherited by direct descendants for the residence nil-rate band to apply.

At current rates, a fully transferable residence allowance could provide up to:

£175,000 + £175,000 = £350,000

When combined with the potential £650,000 ordinary nil-rate band, the total reaches £1 million.

What Happens If the Estate Is Worth More Than £2 Million?

Larger estates face an additional restriction.

The residence nil-rate band starts to reduce where the net estate is worth more than £2 million.

HMRC applies a taper that removes £1 of residence nil-rate band for every £2 by which the estate exceeds £2 million.

This means families with higher-value estates should not simply assume that the full £175,000 or £350,000 residence allowance remains available.

For sufficiently large estates, the residence nil-rate band can disappear completely.

The ordinary £325,000 nil-rate band and any transferable unused basic nil-rate band are governed separately.

Example: Second Parent Dies With a £900,000 Estate

Consider a simplified example.

The first parent dies and leaves everything to their spouse. Their ordinary nil-rate band and residence nil-rate band remain fully unused.

Several years later, the second parent dies with an estate worth £900,000, including a qualifying family home that passes to their children.

If all conditions for both transferred allowances and the residence nil-rate band are satisfied, the estate could potentially have:

• £325,000 of the second parent’s nil-rate band;
• £325,000 transferred from the first parent;
• £175,000 residence nil-rate band; and
• £175,000 transferred residence nil-rate band.

That provides a potential combined threshold of £1 million.

Because the £900,000 estate is below that amount, there could be no Inheritance Tax to pay in this simplified example.

Actual calculations can differ because of lifetime gifts, trusts, debts, property ownership, reliefs, the terms of the wills and other circumstances.

Example: Second Parent Dies With a £1.2 Million Estate

Suppose instead that the qualifying estate is worth £1.2 million and the full £1 million of allowances is available.

The simplified calculation would be:

Estate: £1,200,000
Available allowances: £1,000,000
Potential taxable amount: £200,000

At the standard 40% IHT rate:

£200,000 × 40% = £80,000

The estate could therefore face an approximate £80,000 Inheritance Tax bill.

This is only an illustration. Executors should calculate the actual estate using HMRC rules rather than treating the £1 million threshold as guaranteed.

What If the Parents Were Not Married?

This is a crucial distinction.

The transferable nil-rate band rules apply to spouses and civil partners.

Simply being a couple, living together for many years or having children together does not automatically create the same transferable Inheritance Tax allowances.

The ability to transfer unused thresholds arises specifically following the death of a spouse or civil partner.

Therefore, where the first and second parents were unmarried and not civil partners, the second parent’s executors cannot normally combine the two parents’ ordinary IHT allowances in the same way.

This can produce a significantly different tax outcome.

Does the First Parent’s Allowance Transfer Automatically?

Executors should not assume the process is completely automatic.

Where a full Inheritance Tax account is required, HMRC provides form IHT402 to claim the transfer of an unused nil-rate band from a previously deceased spouse or civil partner.

Evidence concerning the first death may therefore be important.

Executors may need information such as:

• the first parent’s date of death;
• their will;
• the value of their estate;
• details of beneficiaries;
• any lifetime gifts;
• previous probate or estate records; and
• how much of their nil-rate band was used.

Estates with older first deaths can consequently require additional investigation.

What About Gifts Made Before the Second Parent Dies?

Lifetime gifts can affect the Inheritance Tax calculation.

HMRC generally considers relevant gifts made during the seven years before death when calculating IHT. Gifts within this period can use some or all of the nil-rate band before it is applied to the remaining estate.

There are also exemptions and specific rules governing gifts, so not every transfer made during a person’s lifetime creates an Inheritance Tax liability.

Executors should therefore establish whether the second parent made significant gifts before death rather than calculating tax solely from the assets still owned at the date of death.

A Major Pension Change Is Coming From April 2027

Families planning estates should also be aware of a significant forthcoming change.

From 6 April 2027, most unused pension funds and pension death benefits will be included within a deceased person’s estate for Inheritance Tax purposes.

The change has been legislated for in Finance Act 2026, according to HMRC’s technical guidance.

At present, many discretionary pension funds can generally pass outside the estate for IHT purposes. The reform could therefore increase the value of some estates that become liable for tax.

HMRC states that personal representatives will be responsible for reporting and paying IHT attributable to relevant unused pension funds and death benefits under the new regime. Registered pension scheme death-in-service benefits are excluded from the reform.

For families dealing with a second parent’s estate after April 2027, pension wealth may therefore become considerably more important to the overall IHT calculation.

When Must Inheritance Tax Be Paid After the Second Parent Dies?

Inheritance Tax normally has to be paid by the end of the sixth month after the month in which the person died.

HMRC can charge interest when tax remains unpaid after the deadline.

Where IHT is due, some tax will normally need to be paid before probate can be obtained.

Certain assets, including qualifying property that may take time to sell, can sometimes be dealt with through yearly instalments.

A full Inheritance Tax account using IHT400 is required where tax is payable or where an estate does not meet the requirements to be treated as an excepted estate.

Are Inheritance Tax Thresholds Increasing?

Families should not currently expect the standard thresholds to rise in the immediate future.

HMRC confirmed in February 2026 that the £325,000 nil-rate band, £175,000 residence nil-rate band and £2 million residence nil-rate band taper threshold are set to remain at their current levels through 5 April 2031.

That means rising property and asset values could bring more estates closer to the tax thresholds even without an increase in real wealth.

What Should Families Check When the Second Parent Dies?

Before deciding whether Inheritance Tax is payable, executors should establish the complete circumstances of both parents’ estates.

Particular attention should be given to whether the parents were married or civil partners, how much of the first parent’s nil-rate band was used, whether a qualifying home passes to direct descendants and whether the first parent’s residence nil-rate band can be transferred.

Lifetime gifts, trusts, business assets, agricultural property and overseas assets can introduce additional rules.

The calculation should therefore be based on the actual estate rather than a general assumption that every married couple automatically receives a £1 million tax-free allowance.

Takeaway

Inheritance Tax when the second parent dies can be significantly more complicated than applying a single £325,000 allowance. Where the parents were married or civil partners, unused allowances from the first death can potentially increase the second parent’s basic nil-rate band to £650,000. A qualifying family home can potentially increase the combined threshold further, reaching as much as £1 million.

However, that figure is conditional rather than guaranteed. Estate size, property inheritance, lifetime gifts, previous use of allowances and the parents’ legal relationship can all affect the calculation.

With existing IHT thresholds now set to remain frozen until April 2031 and most unused pension wealth entering the IHT regime from April 2027, families administering larger estates may need to pay closer attention to the rules than ever before.