Valuing a house for probate: RICS surveys, estate agent letters and what HMRC accepts

If the person who died owned a house or flat, one of the first practical jobs facing an executor is working out what it was worth on the day they died. That figure feeds into almost everything that follows – whether Inheritance Tax is due, how much, and what the property’s value will be treated as for capital gains tax if it’s later sold. Getting it right matters more than most executors realise, and getting it wrong can be expensive in both directions: overstate it and you may pay tax you didn’t need to; understate it and HM Revenue & Customs (HMRC) can query the figure, sometimes years after probate has been granted.

This guide explains what a probate valuation needs to show, the difference between a free estate agent appraisal and a formal RICS valuation, when each one is enough for HMRC, and what to do if a valuation is later found to be wrong.

Why probate needs a property valuation at all

Probate is the legal process of establishing who has the right to deal with someone’s estate. Before an executor can apply for the grant, they need to add up the value of everything the deceased owned – savings, investments, possessions, and property – to work out whether Inheritance Tax is due, and if so, how much (gov.uk – Valuing the estate of someone who died).

For most families, the house is the single largest asset in the estate, often worth more than everything else put together. HMRC’s own guidance for completing form IHT400, the main Inheritance Tax account, puts it plainly: “valuing land and buildings can be a complicated area and you’re strongly advised to use a professional valuer” (gov.uk – IHT400 Notes: guide to completing your Inheritance Tax account). Property doesn’t have a market price you can look up the way you can with quoted shares or a bank balance – it has to be independently assessed, and that assessment becomes the figure HMRC works from.

The valuation matters for two separate reasons, not just one:

• Inheritance Tax. The property’s value is added to the rest of the estate to work out whether the estate exceeds the available nil-rate bands, and if so, how much tax is due.
• Capital gains tax later. If the property is sold by the estate or the beneficiaries for more than its value at the date of death, capital gains tax may be due on the difference. The probate value becomes the new “base cost” for that calculation. An artificially low probate valuation might look like it reduces Inheritance Tax now, but it can create a much larger capital gains tax bill down the line – see our full guide to inheritance tax on property for how the two taxes interact.

What “open market value” means

HMRC does not want the amount the house is insured for, what it might fetch in a rushed sale, or a sentimental guess. It wants the open market value at the date of death: the price a willing buyer would have paid a willing seller if the property had been properly marketed, with both sides having full knowledge of its condition and the local market (gov.uk – Valuing the estate of someone who died). This is the same standard used across HMRC’s guidance for any asset that doesn’t have a fixed, quoted price.

Whoever values the property – an estate agent or a chartered surveyor – needs to be told explicitly that this is the figure you need. HMRC’s own IHT400 notes are specific about this: “remember to tell the valuer that you want the open market value” of the asset, not an insurance or replacement value.

A few things the valuer should take into account when arriving at that figure:

• The property’s condition and state of repair, which can reduce the value
• Any features that might make it more attractive to a developer – a large garden, potential for extension, or access to adjoining land suitable for building – which can increase it
• Local sales of comparable properties around the date of death, not current asking prices

Estate agent letter or RICS valuation – which do you need?

This is the question most executors get stuck on, and the honest answer is: it depends on the estate.

The two routes carry different weight because they’re suited to different levels of risk. An estate agent’s letter is a commercial opinion, useful and usually reliable, but not independently produced to a professional standard – so it takes several of them, averaged, to give HMRC comparable confidence to the one that a single Red Book report provides on its own.

When an estate agent’s letter is enough

HMRC does not insist on a formal RICS valuation for every estate. Where the total estate is comfortably below the Inheritance Tax threshold – so there is no realistic prospect of a dispute about the tax due – a written valuation from an estate agent, or an average of a few such valuations, is generally accepted as reasonable evidence of open market value. This reflects the same “reasonable estimate, not a precise figure to the penny” standard HMRC applies to the rest of the estate.

If you go this route, get more than one opinion where possible, get it in writing on the agent’s letterhead, and keep it on file with the rest of your probate paperwork. A single verbal estimate from one agent is weaker evidence than several written letters that broadly agree with each other.

When you should get a formal RICS valuation

A formal valuation from a member of the Royal Institution of Chartered Surveyors (RICS), prepared in line with the RICS Valuation – Global Standards (commonly known as the Red Book), is worth commissioning when:

• The estate is close to, at, or over the Inheritance Tax nil-rate band and residence nil-rate band thresholds, so the property’s value could change whether tax is due, or how much
• The property is unusual – a farmhouse, a property with development potential, a listed building, or one in poor condition – where an estate agent’s market-comparison approach is less reliable
• There are multiple beneficiaries who may disagree about the property’s value, since an independent professional report is harder to dispute than an estate agent’s opinion
• You expect the property might be sold well above or below the figure you’re planning to declare, which could later attract HMRC’s attention

RICS members work to the Red Book, which sets out mandatory practices for valuations carried out for financial, statutory and taxation purposes, including the kind of valuation commonly (if informally) referred to as a “probate valuation” (RICS – Red Book). A Red Book report carries more independent standing than an estate agent’s letter because it follows a recognised professional standard, is backed by professional indemnity insurance, and is prepared by someone with no commercial interest in the outcome of a sale.

There is no fixed national fee scale for these valuations. Our probate costs guide estimates a typical RICS property valuation at roughly £150–£500, with the exact cost depending on the property’s size, location and complexity. Get a quote before instructing anyone, since costs vary between surveyors and regions.

What HMRC does with the figure

Once a valuation is submitted with the Inheritance Tax return, HMRC does not simply take it on trust and file it away. Property valuations reported on form IHT405 (the schedule for houses, land and buildings that sits alongside the main IHT400 account) can be referred to HMRC’s own valuation arm, the Valuation Office Agency, whose surveyor is known as the District Valuer. The District Valuer compares the declared figure against Land Registry sale prices, other market evidence, and – if the figure looks low – may query it directly with the executor (gov.uk – IHT400 Notes).

If HMRC’s valuer doesn’t accept the figure submitted, they will usually try to agree a value with the executor rather than impose one unilaterally. If an agreed value later turns out higher than the one first declared, the estate may owe more tax, plus interest on the difference from the date the tax was originally due.

If you get more than one valuation and they disagree

It’s common for two or three valuations of the same property to come back with different figures – valuation is a matter of professional judgement, not an exact science. HMRC’s own guidance addresses this directly: where you have several valuations giving a range of figures, “it’s probably best to adopt a value that’s somewhere in between the highest and lowest values that you’ve got,” rather than simply picking the lowest one.

If the valuation turns out to be wrong

Sometimes new information comes to light after a valuation has been obtained but before probate is finalised – most commonly, the property goes on the market and offers come in noticeably above or below the figure used. HMRC’s guidance says this needs to be reconsidered: if, for example, a valuation put the property at £250,000 but marketing it produces credible offers around £270,000, that’s evidence the open market value may be closer to £270,000. In that situation, HMRC recommends going back to the valuer and asking them to consider amending the figure, taking into account the time that has passed since the death and any movement in the property market since.

This cuts both ways. If a valuation looks too high once the property is marketed and offers fall well short, that’s also evidence worth taking back to the valuer, and can support a reduction in the figure originally submitted, provided the drop reflects genuine market conditions rather than an attempt to sell in a hurry.

Undervaluing is a false economy

It can be tempting to lean towards a lower figure to reduce an Inheritance Tax bill, but this rarely works out well for the estate. Deliberately understating a property’s value is something HMRC can investigate and penalise, and – as explained above – it stores up a larger capital gains tax bill for the beneficiaries when the property is later sold. An accurate figure, backed by proper evidence, protects the estate on both fronts – see inheritance tax on property for more on how the two taxes interact.

Valuing a share of a jointly owned property

If the deceased owned the property jointly with someone else, only their share is valued for the estate – but the arithmetic isn’t as simple as dividing the total value by the number of owners. HMRC’s guidance allows for a discount to reflect the fact that a part-share in a property is generally harder to sell than the whole. In England and Wales, a starting point of a 10% reduction on the arithmetical share is commonly applied, though the actual figure depends on the circumstances of the property and can be higher or lower. This discount does not apply where the other joint owner is the deceased’s spouse or civil partner – in that case, the arithmetical share is used without any reduction.

How the property was owned also affects whether it needs probate at all. See our guide to do you need probate for how jointly owned assets, held as joint tenants versus tenants in common, are treated differently.

Step-by-step: getting a property valued for probate

Many estates now qualify for simpler reporting under the “excepted estates” rules if there is clearly no Inheritance Tax to pay, in which case the full IHT400 process isn’t needed – see our guide on how to apply for probate for how that fits into the wider application.

If you’re not sure which route applies

Property valuation is one of the few areas of probate where a second opinion costs relatively little compared with the risk of getting it wrong. If you’re unsure whether your estate needs a formal RICS valuation, HMRC’s Inheritance Tax helpline (0300 123 1072) can tell you what level of evidence they’d expect for your circumstances before you pay for anything. If the estate is complex – disputed beneficiaries, business or agricultural property, assets overseas – a probate solicitor can advise on the valuation alongside the rest of the application.

For the wider probate process, see our guide to how to apply for probate, do you need probate, and the full breakdown of probate costs. For how property fits into the Inheritance Tax calculation itself, see inheritance tax on property.