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

This site is part of QuickSolve HQ, a small group of free UK tools. You can find the others at quicksolvehq.com.

IHT Calculator UK is run by the IHT Calculator UK team. We build free financial calculator tools for UK consumers.

Contact

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