# IHT Interest Series

> The IHT Interest Series carries 6 published figures read from 2 sources' own pages; the 4 published figures given by rate run from 0.50 to 7.75 percent, read 17 October 2026.

Corp Tax Calculator · https://corptaxcalculator.co.uk/datasets/iht-interest-series/ · computed 2026-10-21

**Range by rate:** 0.5 to 7.75 % (range 0.5 to 7.75 %; 6 published figures; 2 of 7 sources read publish one).

2 of the 7 named sources read in full publish a figure; 5 publish none, read 17 October 2026.

## By rate and spread over Bank Rate

| Breakdown | Median | Range | Sources |
|---|---|---|---|
| rate Bank of England Bank Rate | 3.75 % | 3.75 to 3.75 % | 1 |
| rate repayment interest minimum floor | 0.5 % | 0.5 to 0.5 % | 1 |
| rate late payment interest | 7.75 % | 7.75 to 7.75 % | 1 |
| rate repayment interest | 2.75 % | 2.75 to 2.75 % | 1 |
| spread over Bank Rate late payment interest, base rate plus | 4 % | 4 to 4 % | 1 |
| spread over Bank Rate repayment interest, base rate minus | 1 % | 1 to 1 % | 1 |

## Every figure, with its source

One row per source: the figure the source's own page publishes, the page, and the day it was read.

| Source | Figure | Breakdown | Read |
|---|---|---|---|
| [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates) | 7.75 % | late payment interest | 2026-10-17 |
| [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates) | 4 % | late payment interest, base rate plus | 2026-10-17 |
| [Bank of England: the interest rate (Bank Rate)](https://www.bankofengland.co.uk/monetary-policy/the-interest-rate-bank-rate) | 3.75 % | Bank of England Bank Rate | 2026-10-16 |
| [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates) | 2.75 % | repayment interest | 2026-10-17 |
| [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates) | 1 % | repayment interest, base rate minus | 2026-10-17 |
| [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates) | 0.5 % | repayment interest minimum floor | 2026-10-17 |

## The sentence each figure was read from (6)

- [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates), read 2026-10-17: "late payment interest rate — 7.75% from 9 January 2026"
- [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates), read 2026-10-17: "late payment interest set at base rate plus 4% from 6 April 2025 (was plus 2.5% on or before 5 April 2025)"
- [Bank of England: the interest rate (Bank Rate)](https://www.bankofengland.co.uk/monetary-policy/the-interest-rate-bank-rate), read 2026-10-16: "Today, we’ve held Bank Rate at 3.75%."
- [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates), read 2026-10-17: "repayment interest rate — 2.75% from 9 January 2026"
- [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates), read 2026-10-17: "repayment interest, set at base rate minus 1%, with a lower limit of 0.5% (known as the ‘minimum floor’)"
- [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates), read 2026-10-17: "Repayment interest will be paid at 0.5% until the Bank of England raises the base rate above 1.5%."

## Read in full, publishes no figure

- [GOV.UK: HMRC interest rates for late and early payments (publication)](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments), read 2026-10-10: read in full and no accepted figure on the page
- [GOV.UK: Rates and allowances - Inheritance Tax thresholds and interest rates](https://www.gov.uk/government/publications/rates-and-allowances-inheritance-tax-thresholds-and-interest-rates), read 2026-10-10: read in full and no accepted figure on the page
- [Bank of England Bank Rate database](https://www.bankofengland.co.uk/boeapps/database/Bank-Rate.asp), read 2026-10-10: read in full and no accepted figure on the page
- [IHTA 1984 s.233: interest on unpaid tax](https://www.legislation.gov.uk/ukpga/1984/51/section/233), read 2026-10-17: read in full and no accepted figure on the page
- [GOV.UK: Inheritance Tax payment deadlines](https://www.gov.uk/paying-inheritance-tax/deadlines), read 2026-09-12: read in full and no accepted figure on the page

## Methodology

Every row is a verbatim sentence read from the named source's own page through our fetch service on the date shown, hash-pinned to the stored read (the sha of the page's visible text; the raw page is mirrored to R2). 2 of the 7 named sources that could be read published a usable figure; 5 published none and are recorded as not published, never filled in; 0 could not be read (blocked, dead or unreachable) and count nowhere. The headline figures (median, minimum, maximum, quartiles) are over ONE figure per source for each breakdown it prices, in % (a source's median where its page yielded several accepted sentences for one breakdown), so a page that gives figures for several breakdowns gives one for each and N counts 6 figures, never sentences; 29 candidate sentence(s) were refused by a reviewer with the reason recorded. The fuller derivation this dataset is chartered to grow into (not yet what the figures above are; they are each source's own published figure as read): the full dated HMRC IHT interest series joined to the Bank of England Bank Rate on the same dates, so interest over any period between a death and a payment is computed rate-segment by rate-segment rather than at today's rate - which is the only correct way to do it and the reason a single-rate calculator is wrong for every estate open across a change. The published figure is the series itself with each change dated, plus the current rate, the spread over base, and the count of changes in the last five years.

## Sources

- [GOV.UK: rates and allowances - HMRC interest rates for late and early payments](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates) (the publisher's own terms; quoted for reporting and comment)
- [GOV.UK: HMRC interest rates for late and early payments (publication)](https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments) (the publisher's own terms; quoted for reporting and comment)
- [GOV.UK: Rates and allowances - Inheritance Tax thresholds and interest rates](https://www.gov.uk/government/publications/rates-and-allowances-inheritance-tax-thresholds-and-interest-rates) (the publisher's own terms; quoted for reporting and comment)
- [Bank of England Bank Rate database](https://www.bankofengland.co.uk/boeapps/database/Bank-Rate.asp) (the publisher's own terms; quoted for reporting and comment)
- [IHTA 1984 s.233: interest on unpaid tax](https://www.legislation.gov.uk/ukpga/1984/51/section/233) (the publisher's own terms; quoted for reporting and comment)
- [GOV.UK: Inheritance Tax payment deadlines](https://www.gov.uk/paying-inheritance-tax/deadlines) (the publisher's own terms; quoted for reporting and comment)
- [Bank of England: the interest rate (Bank Rate)](https://www.bankofengland.co.uk/monetary-policy/the-interest-rate-bank-rate) (the publisher's own terms; quoted for reporting and comment)

## Cite or embed

- The IHT Interest Series carries 6 published figures read from 2 sources' own pages; the 4 published figures given by rate run from 0.50 to 7.75 percent, read 17 October 2026.
- 2 of the 7 named sources read in full publish a figure; 5 publish none, read 17 October 2026.
- IHT Interest Series, rate Bank of England Bank Rate: median 3.75 percent across 1 source, read 17 October 2026.
- IHT Interest Series, rate repayment interest minimum floor: median 0.50 percent across 1 source, read 17 October 2026.
- IHT Interest Series, rate late payment interest: median 7.75 percent across 1 source, read 17 October 2026.
- IHT Interest Series, rate repayment interest: median 2.75 percent across 1 source, read 17 October 2026.
- IHT Interest Series, spread over Bank Rate late payment interest, base rate plus: median 4 percent across 1 source, read 17 October 2026.
- IHT Interest Series, spread over Bank Rate repayment interest, base rate minus: median 1 percent across 1 source, read 17 October 2026.

Cite as: "Corp Tax Calculator IHT Interest Series", updated 2026-10-21, https://corptaxcalculator.co.uk/datasets/iht-interest-series/.

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