Probate IHT400 Estate Calculator 2026/27
Estimate IHT liability for probate. NRB £325,000 + RNRB £175,000 stacking. 40%/36% rate. Above £2m taper.
Estate scenarios
| Scenario | Estate value | Taxable | Rate | IHT |
|---|---|---|---|---|
| Modest estate £400k | £400,000 | £0 | 40% | £0 |
| Mid estate £750k | £750,000 | £250,000 | 40% | £100,000 |
| Large estate £1.5m | £1,500,000 | £1,000,000 | 40% | £400,000 |
| Large with charity 10% | £1,500,000 | £850,000 | 36% | £306,000 |
| Above taper £2.5m | £2,500,000 | £2,175,000 | 40% | £870,000 |
| £5m estate | £5,000,000 | £4,675,000 | 40% | £1,870,000 |
Frequently asked questions
NRB + RNRB stacking
NRB £325k + RNRB £175k (if main residence to descendants) = £500k single, £1m couple via spouse transfer. RNRB taper above £2m estate.
Charitable 10% rule
If 10%+ of net estate to charity, residual estate IHT rate reduces from 40% to 36%. Section 8C IHTA 1984.
14 IHT400 supplement forms
IHT402 (transfer NRB), 403 (gifts), 405 (property), 406 (banks), 407 (chattels), 408 (jewellery), 409 (pensions), 410 (life insurance), 411 (shares), 412 (unlisted shares), 413 (BPR/APR), 416 (debts), 418 (trusts), 421 (probate summary).
IHT payment deadline
6 months from end of death month. Interest charged thereafter (BoE base + 4%). Direct payment from deceased's account possible pre-probate.