Transferable Nil-Rate Band UK 2026: How to Claim a Deceased Spouse's IHT Allowance
Updated 15 May 2026 · 9 min read · England & Wales
When a spouse or civil partner dies, any portion of their nil-rate band (NRB) that was not used against their estate can be transferred to the surviving spouse. On the survivor's death, the executor claims this unused allowance using HMRC form IHT402, potentially saving up to £130,000 in inheritance tax (40% of £325,000). This is one of the most valuable IHT reliefs available and is routinely missed.
What Is the Transferable Nil-Rate Band?
The nil-rate band (NRB) is the amount each person can leave free of inheritance tax — currently £325,000, frozen until April 2030. Gifts between married spouses and civil partners are fully exempt from IHT (the spouse exemption), so when one spouse leaves everything to the other, none of their NRB is used. The Finance Act 2008 introduced the transferable NRB (TNRB): the unused proportion of the first spouse's NRB transfers to the survivor, increasing the threshold available on the second death.
The maximum transfer is 100% — giving the survivor a combined NRB of £650,000. This applies where the first spouse used none of their NRB (typically because everything passed to the survivor or to charity).
Who Can Claim the Transferable Nil-Rate Band?
The TNRB is available to:
- Surviving spouses (legally married)
- Surviving civil partners (in a registered civil partnership)
It is not available to:
- Cohabiting couples, regardless of the length of the relationship
- Engaged couples who were not yet married when one died
- Divorced spouses (where the divorce was finalised before the first death)
A survivor can claim from multiple deceased spouses, but the maximum transferable amount is capped at 100% — you cannot accumulate more than one additional NRB even if you have been widowed multiple times.
How the Calculation Works
The TNRB is calculated as a percentage of the first spouse's NRB at their death, then applied to the NRB at the second death:
- Step 1 — Find the first spouse's NRB at their death. The NRB has changed over the years. HMRC provides historical NRB values: for example, the NRB was £325,000 from April 2009 to today; £312,000 in 2008/09; £300,000 in 2007/08.
- Step 2 — Calculate how much of that NRB was used. The NRB is used by: chargeable transfers in the 7 years before death (gifts to non-exempt beneficiaries) plus chargeable estate (assets not passing to the surviving spouse or charities).
- Step 3 — Express the unused amount as a percentage of the first NRB.Example: first spouse's NRB was £325,000; they left £75,000 to children. Used: £75,000 / £325,000 = 23.1%. Unused: 76.9%.
- Step 4 — Apply the unused percentage to the current NRB. Survivor's NRB at second death: £325,000. TNRB: 76.9% × £325,000 = £249,925. Total threshold: £325,000 + £249,925 = £574,925.
Worked Examples
Example 1: Full Transfer (100%)
David dies in 2015, leaving everything to his wife Susan (fully exempt — no NRB used). Susan dies in 2026 with an estate worth £800,000.
- Susan's own NRB: £325,000
- Transferred NRB (100% of David's): £325,000
- Total threshold: £650,000
- Taxable estate: £800,000 − £650,000 = £150,000
- IHT at 40%: £60,000
Without the TNRB, the IHT would have been £190,000. The TNRB saves £130,000.
Example 2: Partial Transfer (50%)
Margaret dies in 2010 when the NRB was £325,000. She leaves £162,500 to her children (chargeable) and the rest to her husband Robert. Robert dies in 2026.
- Margaret's NRB used: £162,500 / £325,000 = 50%
- Unused: 50%
- TNRB: 50% × £325,000 (current NRB) = £162,500
- Robert's total threshold: £325,000 + £162,500 = £487,500
How to Claim: Form IHT402
The TNRB is claimed by completing HMRC form IHT402 (Claim to transfer unused nil rate band) as a supplementary schedule to the main IHT400 inheritance tax account for the second estate. IHT402 asks for:
- Details of the first spouse (name, date of death, domicile)
- Whether probate or letters of administration were obtained for the first estate
- The gross value of the first estate
- Chargeable transfers made by the first spouse in the 7 years before their death
- The value of assets that did not benefit from the spouse or charity exemption
- The resulting unused percentage
Supporting Evidence Required
- Death certificate of the first spouse
- Grant of probate or letters of administration for the first estate (if obtained)
- Copy of the first spouse's will (if they had one)
- Evidence of estate value at the first death if no grant was obtained (bank statements, solicitor correspondence, IHT returns if any)
For old deaths where records are incomplete, HMRC will often accept a statutory declaration from the executor setting out the circumstances. Evidence of a pre-1975 first death is particularly difficult to obtain — HMRC generally accepts an assumed 100% transfer for deaths before 13 November 1974 unless clear evidence shows the NRB was used.
When Does the Claim Not Require IHT400?
If the combined estate (including the TNRB) is below the IHT threshold — i.e., the estate would be an excepted estate even before considering the TNRB — no IHT400 or IHT402 is required. The executor confirms the excepted estate status in the probate application (PA1P), ticking the relevant box to indicate a deceased spouse's NRB is being transferred. HMRC may request evidence after the grant is issued if they have doubts.
From 1 January 2022, most excepted estates no longer need to complete IHT205 — the confirmation is built into the probate application form.
The Transferable Residence Nil-Rate Band
Alongside the transferable NRB, a surviving spouse can also claim the deceased spouse's unused residence nil-rate band (RNRB) — currently £175,000. This is claimed on form IHT436 (Claim to transfer unused residence nil-rate band).
A couple can therefore pass up to £1 million free of IHT:
| Allowance | Amount |
|---|---|
| Survivor's own NRB | £325,000 |
| Transferred NRB (up to 100%) | £325,000 |
| Survivor's own RNRB | £175,000 |
| Transferred RNRB (up to 100%) | £175,000 |
| Combined maximum | £1,000,000 |
The RNRB requires leaving a qualifying residential property to direct descendants (children, grandchildren, stepchildren treated as children) directly or via a life interest trust. It is tapered away for estates above £2 million (£1 RNRB lost for every £2 above the threshold).
Common Mistakes When Claiming
- Not claiming at all — the most common error. Executors who do not know about the TNRB pay IHT that was never due.
- Assuming 100% when less is available — if the first spouse made gifts to children or left assets to non-exempt beneficiaries, the full 100% is not available.
- Failing to obtain evidence — HMRC may reject an unsupported claim. Gather evidence of the first death as part of estate administration.
- Forgetting the TRNRB — claiming the TNRB without also claiming the transferable RNRB (IHT436) if it applies.
- Using the wrong NRB at first death — using today's NRB to calculate the first estate's position instead of the NRB applicable at the date of first death.
Frequently Asked Questions
What is the maximum transferable nil-rate band a surviving spouse can claim?
A surviving spouse or civil partner can claim up to 100% of one additional nil-rate band — effectively doubling their own threshold. At the current NRB of £325,000, this gives a maximum combined threshold of £650,000. The 100% maximum applies regardless of how many former spouses or civil partners the survivor has had: you cannot accumulate more than 100% from multiple deceased spouses. If a deceased first spouse left assets up to their full NRB to non-exempt beneficiaries (typically children), little or none of their NRB transfers. If they left everything to the surviving spouse (fully exempt), 100% transfers. The transferable residence nil-rate band (TRNRB) can add a further £175,000 per eligible deceased spouse, potentially giving a maximum combined threshold of £1 million (£325,000 NRB + £325,000 TNRB + £175,000 RNRB + £175,000 TRNRB).
Is there a time limit for claiming the transferable nil-rate band?
There is no fixed statutory deadline for claiming the TNRB in isolation — the claim is made as part of the IHT return for the second estate (IHT400 with supplementary form IHT402). However, IHT on the second estate must be paid within six months of the month of the second death, after which interest accrues. If the second estate is an excepted estate (below the threshold even before the TNRB is considered), the claim can be made without filing an IHT400 — the executor simply confirms the excepted estate status, which includes the TNRB. HMRC can open compliance checks for up to 4 years (or 20 years for deliberate errors) after the tax year in which IHT was due, so it is important to claim correctly at the time.
What evidence does HMRC require for an IHT402 claim?
HMRC requires documentary evidence to support the percentage of unused NRB. For IHT402 you need: (1) a copy of the first spouse's death certificate; (2) a copy of the first spouse's grant of probate or letters of administration (if one was obtained); (3) if a grant was not obtained, other evidence of the estate value at the first death — a bank statement, solicitor's letter, or correspondence confirming the estate was below the IHT threshold; (4) if the first spouse left a will, a copy of that will to show how the estate was disposed of; (5) form IHT402 itself, completed with the calculation of the unused percentage. HMRC may request additional evidence, particularly for older deaths where records may be incomplete.
What happens if the first spouse died before 13 November 1974?
The transferable nil-rate band provisions (Finance Act 2008) apply to the second death on or after 9 October 2007, regardless of when the first spouse died. There is no lower cut-off date for the first death — if the first spouse died in 1960 and the survivor dies in 2026, the unused NRB from 1960 can still be transferred. The percentage calculation uses the NRB applicable at the first death, expressed as a proportion of the NRB at that time — but because the transferred amount applies to the current NRB at the second death, this effectively means the full £325,000 (or 100%) is available on the second death if 100% was unused at the first. HMRC accepts that for deaths before October 1974, the 100% unused NRB can generally be assumed unless evidence shows otherwise.
Can the transferable nil-rate band be claimed if the first estate was subject to IHT?
Yes — but the amount transferred is reduced proportionally. The TNRB is calculated as a percentage: the unused proportion of the first spouse's NRB at their death, applied to the NRB at the second death. If the first spouse used 50% of their NRB (leaving £162,500 to non-exempt beneficiaries at a time when the NRB was £325,000), then 50% transfers — giving an additional £162,500 on the second death. The calculation compares: (a) the value of chargeable transfers made by the first spouse in the 7 years before death plus the chargeable estate; versus (b) the NRB at the first death. The unused fraction is expressed as a percentage and applied to the current NRB.
Does the transferable nil-rate band apply to cohabiting couples?
No. The transferable nil-rate band is only available to legally married spouses and registered civil partners. It does not apply to cohabiting couples, regardless of the length of the relationship or whether they have children together. This is one of the most significant tax disadvantages of cohabitation: an unmarried couple cannot transfer unused NRB, meaning the second death could face an IHT bill even though the first death was entirely within the individual threshold. Marriage or civil partnership eliminates this gap. For unmarried couples with IHT exposure, specialist trust and estate planning is required to achieve a comparable result.
Make a Will to Protect the Full £1 Million Threshold
A well-drafted will ensures the RNRB is available on the first and second death — for example, by leaving the family home to direct descendants via a life interest trust. Without a will, the intestacy rules may distribute your estate in a way that wastes part of this allowance. Our DIY will kit includes plain-English guidance on maximising both NRB and RNRB.
Get the WillSafe Kit →Related Articles
- Transferable nil-rate band — overview and rules
- Nil-rate band explained
- Residence nil-rate band — how to qualify
- IHT planning: 12 legal strategies
- Every IHT relief and exemption
- Calculate your IHT bill step by step
- Spouse exemption — unlimited IHT-free transfers
This article is for general information only and does not constitute tax or legal advice. TNRB calculations can be complex, particularly for older deaths or partial NRB use. Always consult a qualified solicitor or tax adviser before submitting an IHT400.