Inheritance tax is often thought of as something that only touches the very wealthy, but HMRC’s latest figures tell a more complicated story. With the tax-free threshold frozen for years and recent reforms widening who pays, more families across Wales are being drawn in, often without realising it.
Researchers at David W Harris & Co have examined HMRC’s most recent constituency-level data for Wales, alongside the figures for every UK region, looking at how many families are affected, how much they pay in total, and how large the average bill is in each area. The aim is to give families a clear, local picture of where inheritance tax falls most heavily and to help them understand their own exposure before it becomes a problem.
Inheritance tax across Wales
The HMRC data gives two measures for each constituency, the number of estates liable and the total tax due, from which we calculated the average bill per estate. Read together, they reveal that the areas with the most affected families are not always the ones facing the largest bills.
How many families are affected
More families face an inheritance tax bill in Monmouth than anywhere else in Wales, with 64 estates liable. Vale of Glamorgan follows on 55, Ceredigion on 52 and Cardiff North on 40. A high count here reflects the number of estates caught by the tax, not the size of the bills, which tell a different story.
The table below details the estates liable for inheritance tax, by constituency:
| Constituency | Estates liable | Total tax | Average per estate |
|---|---|---|---|
| Monmouth | 64 | £10m | £156,300 |
| Vale of Glamorgan | 55 | £8m | £145,500 |
| Ceredigion | 52 | £12m | £230,800 |
| Cardiff North | 40
| £6m
| £150,000
|
| Cardiff South and Penarth | 39
| £7m
| £179,500
|
| Gower
| 39
| £7m
| £179,500
|
| Carmarthen West and South Pembrokeshire
| 38
| £6m
| £157,900
|
| Montgomeryshire
| 37
| £8m
| £216,200
|
| Ynys Môn
| 37
| £4m
| £108,100
|
| Dwyfor Meirionnydd
| 34
| £5m
| £147,100
|
| Aberconwy
| 31
| £12m
| £387,100
|
| Brecon and Radnorshire
| 30
| £6m
| £200,000
|
The total tax paid
Aberconwy and Ceredigion have the joint highest total inheritance tax bills of any Welsh constituency, at around £12 million each, despite not having the most estates. That points to a smaller number of higher-value estates rather than sheer volume. Monmouth follows on roughly £10 million, then Montgomeryshire and Vale of Glamorgan on around £8 million each, though for different reasons: Monmouth’s total rests on having the most estates, while the others are driven by larger individual bills.
The following table lists the constituencies ordered by total inheritance tax:
| Constituency | Total tax | Estates liable | Average per estate |
|---|---|---|---|
| Aberconwy | £12m | 31 | £387,100 |
| Ceredigion | £12m | 52 | £230,800 |
| Monmouth | £10m | 64 | £156,300 |
| Montgomeryshire | £8m | 37 | £216,200 |
| Vale of Glamorgan | £8m | 55 | £145,500 |
| Cardiff South and Penarth | £7m | 39 | £179,500 |
| Gower | £7m | 39 | £179,500 |
| Brecon and Radnorshire | £6m | 30 | £200,000 |
| Cardiff North | £6m | 40 | £150,000 |
| Carmarthen West and South Pembrokeshire | £6m | 38 | £157,900 |
| Dwyfor Meirionnydd | £5m | 34 | £147,100 |
| Ynys Môn | £4m | 37 | £108,100 |
The average bill per estate
On the measure that says most about the size of a single family’s bill, the average per estate, Aberconwy leads again at around £387,100. Ceredigion, Montgomeryshire, Brecon and Radnorshire, Cardiff South and Penarth, Gower, and Carmarthen West and South Pembrokeshire follow. These seven constituencies sit above the all-Wales average of roughly £156,800, whilst Monmouth, Cardiff North, Dwyfor Meirionnydd, Vale of Glamorgan and Ynys Môn sit below it.
At the other end, Ynys Môn recorded the lowest average among published areas at £108,100.
The table below ranks the constituencies by the highest average bill per estate:
| Constituency | Average per estate | Estates liable | Total tax |
|---|---|---|---|
| Aberconwy | £387,100 | 31 | £12m |
| Ceredigion | £230,800 | 52 | £12m |
| Montgomeryshire | £216,200 | 37 | £8m |
| Brecon and Radnorshire | £200,000 | 30 | £6m |
| Cardiff South and Penarth | £179,500 | 39 | £7m |
| Gower | £179,500 | 39 | £7m |
| Carmarthen West and South Pembrokeshire | £157,900 | 38 | £6m |
| Monmouth | £156,300 | 64 | £10m |
| Cardiff North | £150,000 | 40 | £6m |
| Dwyfor Meirionnydd | £147,100 | 34 | £5m |
| Vale of Glamorgan | £145,500 | 55 | £8m |
| Ynys Môn | £108,100 | 37 | £4m |
Across Wales as a whole, around 982 estates were liable for inheritance tax in 2023-24, owing a combined total of roughly £154 million, or about £156,800 on average per estate.
How Wales compares with the rest of the UK
Set against the other UK regions and nations, Wales sits at the bottom for the size of the average bill. At around £156,800, the Welsh average ranks 12th. London, by contrast, averaged around £297,300, roughly double the Welsh figure.
The gap likely reflects lower average property and asset values across much of Wales, though, as the constituency figures show, there is plenty of local variation behind that headline.
The table below ranks the regions and nations by average IHT per estate:
| Region | Average IHT per estate | Estates liable | Total tax |
|---|---|---|---|
| London | £297,300 | 4,810 | £1,430m |
| South East | £290,000 | 6,310 | £1,830m |
| Scotland | £228,400 | 1,620 | £370m |
| South West | £202,000 | 3,450 | £697m |
| Yorkshire and the Humber | £195,300 | 1,490 | £291m |
| East of England | £193,600 | 3,300 | £639m |
| East Midlands | £188,800 | 1,430 | £270m |
| West Midlands | £188,200 | 1,860 | £350m |
| North East | £176,400 | 533 | £94m |
| Northern Ireland | £173,300 | 352 | £61m |
| North West | £163,900 | 2,080 | £341m |
| Wales | £156,800 | 982 | £154m |
What this means for families in Wales
A lower average does not mean Welsh families can safely assume the tax will pass them by. The nil-rate band, the threshold at which inheritance tax starts to apply, has sat at £325,000 for years. As house prices and savings grow, estates whose owners would never describe themselves as wealthy can quietly cross that line.
The position has shifted again for families with farming or business assets. Reforms to Agricultural Property Relief and Business Property Relief, which took effect on 6 April 2026, have capped reliefs that used to be unlimited, bringing parts of larger qualifying estates within reach of inheritance tax for the first time. Several of the Welsh areas with higher average bills are rural, so this matters in particular for families who hold land or run a family business.
For most people, the protections are straightforward: keep a Will that is up to date, revisit it whenever circumstances or the value of an estate change meaningfully, and take advice before relying on any relief or exemption.
Tom Baker, Partner at the firm, commented, “Inheritance tax is no longer something that worries only the largest estates. With thresholds fixed and property values climbing, more families across Wales are finding themselves within scope, often without realising it.
“The differences between communities show how much individual circumstances matter, and that is exactly why early, tailored advice is so valuable. A well-kept Will and a clear understanding of the reliefs available can spare a family a great deal of difficulty later on.”
Methodology and data sources
This analysis is based on HMRC’s most recent published inheritance tax statistics by parliamentary constituency and by UK region, covering the 2023-24 tax year. This is the latest data available, as HMRC publishes with a lag of around two years owing to the time probate cases take to complete.
The figures relate to estates that were liable for inheritance tax following a death. The tax was assessed at that point and, in the great majority of cases, has already been paid. They are not outstanding debts or future liabilities.
For every area, both constituencies and UK regions, the number of estates liable and the total tax due are HMRC's official published figures. The average tax per estate is our own calculation, dividing the total tax by the number of liable estates. As HMRC rounds the totals, these averages are approximate.
The constituency figures use the pre-July 2024 Westminster boundaries, comprising 40 Welsh constituencies. HMRC withholds figures where the number of liable estates is small, to protect the confidentiality of individual taxpayers. On this release, 28 of the 40 Welsh constituencies fall below that threshold, so they do not appear in the rankings. A withheld figure does not mean no estates were affected, only that the number was too small to publish.
The 2023-24 figures predate the reforms to agricultural and business property relief that took effect in April 2026, and so reflect the position before those changes.
Any conclusions drawn from the data are those of the David W Harris & Co researchers.
