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Property is the most common source of IHT disputes in probate — and the most common reason HMRC opens a compliance check. Whether you have innocently used an estate agent's low estimate or genuinely struggled to value a complex property, this guide explains what HMRC expects, how they check values, what happens when they query your figure, and how to correct a valuation error. For a broader look at avoiding HMRC investigations, see our guide on how to avoid an HMRC inheritance tax investigation.
The legal standard for valuing property for inheritance tax is "open market value at the date of death". This is defined in section 160 of the Inheritance Tax Act 1984 as the price a willing buyer would pay a willing seller in an arm's-length transaction, with both having reasonable knowledge of the relevant facts.
This is not the price the family would accept in a quick sale, the price the property would fetch if sold in its current condition without any marketing, or the price based on what was paid for it many years ago. It is the full market value as if the property were offered properly on the open market.
Deductions can legitimately be made for genuine factors that would affect value — for example, structural problems, required repairs, or an ongoing tenancy. However, these deductions must be supported by evidence. For guidance on the full valuation process, see our guide to valuing property for probate.
HMRC's Compliance team uses several tools to check property values declared in probate returns:
Land Registry sold price data is publicly available and comprehensive. HMRC can search for properties in the same street or postcode that sold in the period around the date of death and compare them to the declared value. If your declared value is materially below comparables, this will flag as a risk.
HMRC has access to Zoopla, Rightmove, and similar tools that provide automated value estimates. These are imperfect — they do not account for condition, internal layout, or local factors — but they provide a quick reference point that will alert HMRC if a declared value appears out of line.
Where a more detailed review is warranted, HMRC will instruct the District Valuer Service — its in-house property valuation team — to carry out an independent assessment. The DVS surveyor will typically inspect the property or carry out a desktop valuation and produce a formal report.
You are not required to accept the DVS figure. If you believe it is too high, you can provide evidence to support your original value or commission an RICS surveyor to produce a counter-report.
There is no formal "tolerance" written into HMRC guidance, but in practice:
Context matters. A modest semi-detached house in a well-documented area with lots of comparables is easier to value consistently than a rural property, a mixed-use building, or a property with unusual features. HMRC understands this.
If HMRC decides to query your property valuation, the typical sequence is:
For guidance on how to respond to HMRC, see our guide on how to respond to an HMRC probate query and our guide specifically on HMRC querying a property valuation.
The DVS negotiation process is a formal but not adversarial one. Both sides are trying to reach an accurate figure, not to score points. The most effective approach is to:
Many DVS challenges are resolved through negotiation without the full disputed figure being applied. A split-the-difference outcome is common.
If the property value is revised upward — either by agreement with HMRC or following a DVS review — additional IHT will be calculated on the difference between the revised value and your original declaration, at 40% (above the nil-rate band).
| Scenario | Additional IHT |
|---|---|
| Property revised up by £50,000; estate already above NRB | £20,000 (40% of £50,000) |
| Property revised up by £50,000; £30,000 already above NRB | £12,000 (40% of the £30,000 above the NRB threshold) |
| Property revised up by £50,000; estate still below NRB | £0 |
Interest accrues at approximately 7.75% per year from the original IHT due date (6 months after the end of the month of death) on the additional tax. For a property dispute that takes 18 months to resolve, the interest on £20,000 of additional IHT would be approximately £2,325.
For more on IHT interest and how it accrues, see our guide to probate delays and IHT interest.
Whether the revision arises from a voluntary correction or following an HMRC query, any change to the estate value after the IHT400 has been submitted is recorded via a C4 corrective account. If the correction results in a higher value (and more IHT), you complete the C4, HMRC issues a revised computation, and you pay the balance plus interest. If the correction results in a lower value (see below), HMRC will arrange a repayment.
Overvaluation is less common than undervaluation but it does happen — particularly where the executor uses a higher than necessary professional valuation in an attempt to be conservative, or where a property sells for less after probate is granted.
Where a property sells in the open market within 4 years of death for less than the IHT value declared, HMRC allows a claim to substitute the sale price for the date-of-death value. This is known as a "sale of land at lower price than IHT value" claim and is made on form IHT38 (or C4 for post-grant corrections). If successful, it reduces the IHT liability and HMRC will repay the overpaid tax with interest.
Penalties apply to IHT errors, not to genuine valuation differences. If your property value was simply lower than HMRC's assessment, and you made a reasonable good-faith effort to establish market value, HMRC should not apply penalties — the difference in value is resolved through the DVS negotiation process.
Penalties become relevant where:
For executors who commissioned proper professional valuations and acted in good faith, penalties are not applied even when the DVS disagrees with the declared figure. See our guide on the consequences of mistakes on a probate application.
The most effective way to avoid a property dispute with HMRC is to invest in the right evidence at the outset:
No. You have the right to challenge the DVS figure by providing evidence to support your own valuation. Instruct an RICS-qualified surveyor to produce a formal report and make representations to the DVS. Many disputes are resolved by agreement at a value between the two positions.
Yes — provided the sale completed within 4 years of the date of death and was an arm's-length transaction with an unconnected buyer. Use form IHT38 or a C4 corrective account to claim substitution of the sale price for the IHT value. HMRC will repay the excess IHT paid plus interest on the repayment.
An estate agent's valuation letter is acceptable evidence for IHT purposes, but it carries less weight than an RICS report in a dispute with the DVS. If the value is challenged, you will be in a stronger position with an RICS report. For straightforward properties in areas with good comparable data, an agent's letter often suffices without a challenge.
HMRC has 4 years from the date the IHT account was delivered to open an enquiry for innocent or careless errors. For deliberate errors, the period extends to 20 years. In practice, most property valuation queries arise within 12–18 months of the IHT400 being submitted.
Yes — condition is a legitimate factor in establishing market value. The key is to document the condition thoroughly (photographs, survey, builder's quotes) and ensure the valuer's letter or report explicitly references the condition and explains the impact on value. HMRC will accept condition-based reductions if they are properly evidenced.
How to get a probate property valuation in the UK: RICS Red Book surveyor, estate agent letters, and HMRC's accepted methods. Avoid underpayment penalties. 2026 guide.
What triggers HMRC to investigate an inheritance tax return, how to present your IHT400 to minimise scrutiny, and why property valuation and gift declaration are the most important factors.
What to do if you make a mistake on your probate application or IHT400. HMRC penalty rules, the C4 corrective account, unprompted disclosure, and executor personal liability explained.
Why HMRC challenges property valuations, how the District Valuer Service works, how to gather comparables, when to get an RICS report, and how to negotiate an agreed value.
HMRC charges 8.75% interest on unpaid inheritance tax. Learn how to pay IHT before probate and avoid unnecessary interest charges.
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