About IHT Calculator UK

IHT Calculator UK is a free tool that estimates the inheritance tax liability on a UK estate. We built it because IHT rules are surprisingly complex once you factor in residence nil-rate bands, transferable allowances, the £2M taper, and the 7-year gift rule. Most people either overpay by not claiming what they're entitled to, or underestimate the bill entirely.

How we calculate

Our calculator models the full IHT computation: estate value, minus liabilities (mortgages, debts), minus exempt gifts (to spouse/charity), minus the nil-rate band (£325,000), minus the residence nil-rate band (£175,000 if conditions are met). The remainder is taxed at 40% (or 36% if the charity condition is met).

For couples, we model the transfer of unused allowances from the first death to the second. For gifts, we apply the 7-year taper relief and offset against the nil-rate band in chronological order (oldest gifts use up the NRB first).

Our sources

• IHT rates and thresholds: HMRC Inheritance Tax manual and published rates
• RNRB rules: HMRC guidance on the residence nil-rate band (IHTM46000+)
• Gift taper relief: HMRC IHT400 guidance notes
• Statistics: HMRC Inheritance Tax statistics (Table 12.1, published annually)

Limitations

We don't model business property relief (BPR), agricultural property relief (APR), or the interactions with trusts. These are specialist areas where a qualified estate planner or solicitor should be consulted. We also assume all assets are situated in the UK; overseas assets may have different treatment depending on domicile status.

Who runs this site

IHT Calculator UK is operated by Quicksolve Digital Ltd, a company registered in England and Wales (Company No. 17385486). We build free financial calculator tools for UK consumers.

Contact

For corrections, data queries, or partnership enquiries: hello@ihtcalculator.uk