To claim the transferable nil rate band, the personal representatives of the second spouse or civil partner to die complete form IHT402 and send it in with form IHT400. The claim transfers any percentage of the first person's unused nil rate band to the survivor's estate, and it generally needs to be made within two years of the end of the month of the second death (gov.uk, transferring unused threshold, as at August 2026, subject to change).
The rest of this guide explains what the transferable nil rate band is, exactly who claims it and when, how the percentage is worked out rather than a fixed cash sum, and which form applies if the estate does not need a full IHT400. Figures are current as at August 2026 and are subject to change.
What is the transferable nil rate band?
Each person has a nil rate band, the amount of an estate that is taxed at 0% before inheritance tax applies. It is currently £325,000 and is frozen at that level until 5 April 2031, the end of the 2030-31 tax year, following the one-year extension announced at the Autumn Budget 2025 (gov.uk, Inheritance Tax thresholds and interest rates, as at August 2026, subject to change). When someone dies and leaves everything to their spouse or civil partner, that transfer is normally exempt, so none of the first person's nil rate band is used. The unused portion can then pass to the survivor's estate on the second death. This is often called the transferable nil rate band, and it is claimed on form IHT402 (gov.uk, form IHT402, as at August 2026, subject to change).
The transfer is not automatic. HMRC does not apply it unless the personal representatives make the claim, which is one of the more common reasons families overpay. For background on how the wider tax works, see our guide to inheritance tax in England and Wales.
Who can claim, and whose estate
The claim is made by the personal representatives of the second person to die, meaning the executors named in the will or the administrators of an intestate estate. The unused band being transferred comes from the first spouse or civil partner to have died, whenever that was. The rules apply to marriages and civil partnerships that ended on death, not on divorce or dissolution (gov.uk, as at August 2026, subject to change).
The date of the first death does not stop a claim. A transfer can be claimed even where the first spouse died many years ago and before the transferable band existed, because the rules look at the position on the second death. Where a survivor had more than one late spouse or civil partner, the total transferred is capped at one additional full nil rate band, so a maximum of 100%.
The deadline to claim
A claim to transfer the unused nil rate band should normally be made within two years of the end of the month in which the second person died, or within three months of the personal representatives first acting if that is later (gov.uk, time limits, as at August 2026, subject to change). HMRC has discretion to accept a late claim in some circumstances, but relying on that is not something the rules promise.
How to claim, step by step
- Establish the first death position. Gather the first spouse or civil partner's death certificate, marriage or civil partnership certificate, a copy of the will or details of intestacy, and any grant of probate. These evidence how much of their nil rate band was used.
- Work out the unused percentage. Calculate what percentage of the nil rate band was used on the first death, then the balance is what transfers. The method is set out below.
- Complete form IHT402. Record the first person's details, the value of anything that did use their band, and the percentage available to transfer (gov.uk, form IHT402, as at August 2026, subject to change).
- Send it with the estate return. IHT402 is filed together with form IHT400 for the second estate. Supporting documents from the first death are enclosed.
Because probate and the inheritance tax account often run alongside each other, it can help to understand the wider sequence in our guide to what probate is and how it works.
Why it is a percentage, not a fixed sum
The transfer works in percentages, not pounds, which matters because the nil rate band has risen over the years. HMRC takes the percentage of the band that was unused on the first death and applies that percentage to the band in force on the second death (gov.uk, calculating the transfer, as at August 2026, subject to change).
| Scenario on first death | Percentage transferred | Added to second estate (2026) |
|---|---|---|
| Everything left to the surviving spouse | 100% | £325,000 |
| Half the band used by gifts to children | 50% | £162,500 |
| £130,000 used against a £325,000 band | 60% | £195,000 |
Illustrative only, based on the £325,000 band. Source: gov.uk, as at August 2026, subject to change.
Which form: IHT402, IHT217 or the probate route
The right form depends on whether the second estate needs a full inheritance tax account. Where a full account is required, IHT402 goes in with IHT400. Where the estate is an excepted estate that does not need a full account, the claim is handled differently depending on the date of death (gov.uk, as at August 2026, subject to change).
| Situation | How to claim the transfer |
|---|---|
| Estate needs a full IHT400 account | Form IHT402 with IHT400 |
| Excepted estate, second death from 1 January 2022 | Claim through the probate application |
| Excepted estate, second death before 1 January 2022 | Form IHT217 (100% transfer only) |
| Estate in Scotland | Form C1 applies to confirmation |
Source: gov.uk/guidance/transferring-unused-basic-threshold-for-inheritance-tax, as at August 2026, subject to change.
A separate claim for the residence band
The transferable nil rate band is not the same as the residence nil rate band, and the two are claimed on different forms. The residence nil rate band, worth up to £175,000 where a home passes to direct descendants, has its own transfer on form IHT436 rather than IHT402 (gov.uk, residence nil rate band forms, as at August 2026, subject to change). Combining both transfers is how some married couples reach a total tax-free figure of up to £1,000,000, though the residence band is withdrawn by £1 for every £2 that an estate exceeds £2,000,000 (gov.uk, passing on a home, as at August 2026, subject to change). Keeping clear records now, including earlier grants and wills, tends to make these claims simpler later, which is one reason estate planning looks at the paperwork as well as the numbers.