Calculate the transferable nil rate band available when the surviving spouse dies. Find total IHT-free allowance including transferred unused NRB and RNRB.
When a married person or civil partner dies leaving their estate to their surviving spouse (using the spouse exemption), the unused portion of their Inheritance Tax Nil Rate Band (NRB) can be transferred to the surviving spouse's estate. The surviving spouse's executors can claim up to 100% of the deceased's NRB (which was unused), doubling the effective NRB available on the second death to up to £650,000 (2 × £325,000).
The Nil Rate Band (NRB) is £325,000 and has been frozen at this level since 2009 and is scheduled to remain frozen until at least 2028. This means inflation has significantly reduced its real value. Married couples and civil partners can transfer unused NRB, giving an effective combined NRB of up to £650,000. The Residence Nil Rate Band (RNRB) of £175,000 per person is also available for qualifying homes left to direct descendants.
The Residence Nil Rate Band (RNRB) is an additional IHT allowance of £175,000 per person (2025/26) for people who leave their main home to direct descendants (children, grandchildren, stepchildren). Like the NRB, unused RNRB can be transferred between spouses. A married couple leaving their home to children could potentially have a combined exempt amount of £1,000,000 (£325,000 NRB + £325,000 transferred NRB + £175,000 RNRB + £175,000 transferred RNRB).
No — assets passed between UK-domiciled spouses and civil partners are completely exempt from Inheritance Tax, regardless of the value. This is the 'spouse exemption'. Because of this, many couples leave everything to each other on first death, allowing 100% NRB transfer on the second death. The IHT is then charged only when the surviving spouse dies.
Yes — you can claim the transferable NRB regardless of when the first spouse died, even if they died before the NRB was introduced. The claim is made on the survivor's estate using HMRC form IHT402. Executors must provide evidence of the first spouse's estate and NRB usage. Claims must be made within two years of the surviving spouse's death (subject to HMRC discretion for late claims).