RNRB Taper Explained: How a £2.3m Estate Loses £50,000 of Residence Nil-Rate Band
The residence nil rate band (RNRB) is worth up to £175,000 per person, but it shrinks once your net estate passes £2,000,000 — falling by £1 for every £2 above that line. On a £2,300,000 estate you are £300,000 over, so £150,000 of RNRB is withdrawn, leaving only £25,000. That lost band would otherwise have sheltered £150,000 from 40% tax — a real cash cost of £60,000 in extra inheritance tax.
What the RNRB is — and why the taper exists
The standard nil rate band (NRB) shelters the first £325,000 of any estate from inheritance tax (IHT). The residence nil rate band is an extra allowance of up to £175,000, available when you leave a qualifying home to direct descendants — children, grandchildren, step-children, adopted or foster children. Together they can lift a single person's tax-free amount to £500,000, and a married couple's to £1,000,000.
Both figures are frozen until at least 5 April 2030 (RNRB) and 5 April 2031 (NRB), per HMRC's published rates and allowances. The RNRB was always intended as relief for ordinary family homes, not large estates — so Parliament built in a clawback. Once your net estate exceeds £2m, the RNRB tapers away.
The taper rule in one line
HMRC states it plainly: "The residence nil rate band will reduce by £1 for every £2 that the estate is worth more than the £2 million taper threshold." (gov.uk — Inheritance Tax: residence nil rate band.)
So the maths is always the same three steps:
- Take the net estate value and subtract £2,000,000.
- Divide the excess by 2 — that is the RNRB withdrawn.
- Deduct it from the RNRB otherwise available; the floor is £0.
| Net estate | Excess over £2m | RNRB withdrawn (÷2) | Single-person RNRB left (of £175k) |
|---|---|---|---|
| £2,000,000 | £0 | £0 | £175,000 |
| £2,100,000 | £100,000 | £50,000 | £125,000 |
| £2,300,000 | £300,000 | £150,000 | £25,000 |
| £2,350,000 | £350,000 | £175,000 | £0 (fully tapered) |
Worked Example — Margaret's £2.3m estate
Margaret, a widow, dies in the 2026/27 tax year. She never used her late husband's allowances (we cover that scenario separately below). Her estate:
| Family home (left to her son) | £900,000 |
|---|---|
| Investments, ISAs and cash | £1,250,000 |
| Car, jewellery, contents | £150,000 |
| Net estate | £2,300,000 |
Step 1 — excess over the threshold: £2,300,000 − £2,000,000 = £300,000.
Step 2 — RNRB withdrawn: £300,000 ÷ 2 = £150,000.
Step 3 — RNRB remaining: £175,000 − £150,000 = £25,000.
Margaret keeps only £25,000 of her RNRB. The £150,000 she lost would have been taxed at 40% had it stayed inside the estate, so the taper costs her beneficiaries £60,000 in extra IHT (£150,000 × 40%). She still has her full £325,000 standard NRB.
Why a single person loses the entire £175,000 at about £2.35m
Because the RNRB falls by £1 for every £2 of excess, it takes £350,000 of excess to wipe out the full £175,000 (£350,000 ÷ 2 = £175,000). That happens at an estate of:
£2,000,000 + £350,000 = £2,350,000.
At or above roughly £2.35m, a single person with one RNRB gets nothing from the residence band — they are back to the bare £325,000 NRB. Every pound between £2m and £2.35m is, in effect, taxed twice as hard as you might expect: once at 40% itself, and again by stripping out RNRB that shelters other assets.
How transferred RNRB from a deceased spouse changes the numbers
When the first spouse or civil partner dies, any unused RNRB transfers to the survivor as a percentage uplift — so a survivor can have up to £350,000 of combined RNRB (their own £175,000 plus a transferred £175,000). But taper is tested against the survivor's whole estate, and it bites against that larger combined band.
The withdrawal is still £1 for every £2 over £2m, so to taper away a full £350,000 combined band you need £700,000 of excess (£700,000 ÷ 2 = £350,000). That point is:
£2,000,000 + £700,000 = £2,700,000.
| Survivor's net estate | Excess over £2m | RNRB withdrawn | Combined RNRB left (of £350k) |
|---|---|---|---|
| £2,300,000 | £300,000 | £150,000 | £200,000 |
| £2,500,000 | £500,000 | £250,000 | £100,000 |
| £2,700,000 | £700,000 | £350,000 | £0 (fully tapered) |
Worked Example — the same £2.3m estate, but with a transferred band
Now suppose Margaret's husband had died first leaving everything to her, so 100% of his RNRB transfers. Her £2.3m estate now claims a combined £350,000 RNRB before taper.
Excess: £2,300,000 − £2,000,000 = £300,000. Withdrawn: £300,000 ÷ 2 = £150,000. Remaining RNRB: £350,000 − £150,000 = £200,000.
Compared with the single-band case (£25,000 left), the transferred band leaves £200,000 of RNRB — £175,000 more shelter, saving a further £70,000 of IHT (£175,000 × 40%). The taper applies to both halves of the band; it does not protect the transferred portion.
Planning levers that pull the net estate back under £2m
Because taper is mechanical, every £2 you can legitimately remove from the taper-test figure restores £1 of RNRB — and shelters £1 from 40% tax in its own right. The main levers, all to be discussed with a qualified adviser:
1. Lifetime gifts (the seven-year rule)
Outright gifts (potentially exempt transfers) drop out of the estate entirely if you survive seven years, and the annual £3,000 gift exemption and gifts out of surplus income reduce the estate immediately. Trimming the net estate from £2.3m to £2.0m here would restore the full £175,000 RNRB and remove £300,000 from the 40% band — see gov.uk — IHT on gifts.
2. Business relief and agricultural relief assets
The value of assets that qualify for business relief is excluded when calculating the £2m taper threshold (the taper test looks at value before such reliefs are notionally re-added). Shifting wealth into genuinely qualifying trading-business or AIM holdings can therefore both reduce the IHT on those assets and rescue the RNRB on the rest. These reliefs are technical and the rules are tightening — take advice before relying on them.
3. Genuine debts and liabilities
The taper test is on the net estate. Outstanding mortgages and legitimate, deductible liabilities reduce the figure compared against £2m. Equity release on a high-value home, used carefully, can lower the net estate — but it also reduces what passes to family, so it is a trade-off, not a free win.
The bottom line: the same estate, taper vs no taper
To show the cash impact, here is Margaret's £2.3m estate (single band, leaving her home to her son) compared in two worlds — one where the taper applies, and one where, through planning, the net estate had instead been kept at exactly £2m so the full RNRB survived.
| Taper applies (£2.3m estate) | Estate kept at £2.0m | |
|---|---|---|
| Net estate | £2,300,000 | £2,000,000 |
| Standard NRB | £325,000 | £325,000 |
| RNRB after taper | £25,000 | £175,000 |
| Total tax-free allowance | £350,000 | £500,000 |
| Taxable estate | £1,950,000 | £1,500,000 |
| IHT at 40% | £780,000 | £600,000 |
The difference is £180,000 of IHT. Of that, £120,000 comes from the £300,000 of extra assets being taxed at 40%, and a further £60,000 comes purely from the taper stripping £150,000 of RNRB. That £60,000 is the cost of the taper itself — and it is the part good planning can target.
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Frequently asked questions
At what estate value does the residence nil rate band start to taper?
The RNRB begins to reduce once the net estate exceeds the £2,000,000 taper threshold. It falls by £1 for every £2 above that figure, so an estate of £2.35m loses the entire £175,000 RNRB and an estate of £2.7m can lose a couple's combined £350,000.
How much RNRB does a £2.3 million estate lose?
A £2.3m estate is £300,000 over the £2m threshold. Divided by 2, that withdraws £150,000 of RNRB. From the maximum £175,000 available to one person, £150,000 is lost, leaving just £25,000 of usable residence nil rate band.
Does transferred RNRB from a late spouse also get tapered?
Yes. Taper is applied to the survivor's whole estate against the £2m threshold, then measured against the combined RNRB (own £175,000 plus the transferred amount). A couple's £350,000 combined band fully tapers away once the survivor's estate reaches roughly £2.7m (£700,000 over £2m ÷ 2 = £350,000).
Is the estate value tested before or after debts and reliefs?
Taper is tested on the net value of the estate before reliefs such as business relief or agricultural relief, but after deducting liabilities like a mortgage. Crucially, lifetime gifts that survive seven years and assets qualifying for business relief reduce the figure used for the £2m taper test, which can restore lost RNRB.
Can I get the RNRB back after it has tapered away?
You cannot reclaim it after death, but during lifetime you can plan to keep the net estate under £2m. Levers include making gifts that survive seven years, holding business-relief-qualifying assets, and ensuring genuine debts are recorded. Each £2 you remove from a tapered estate restores £1 of RNRB.
Do you still need to leave a home to children for the RNRB to apply?
Yes. Even before taper, the RNRB only applies where a qualifying residential interest passes to direct descendants such as children, grandchildren or step-children. Taper is a second, separate restriction layered on top of that qualifying-home condition.
General information, not personal United Kingdom tax/legal advice. Verify with a qualified professional.
Sources: GOV.UK — Inheritance Tax: residence nil rate band; Inheritance Tax overview; Rates and allowances: IHT thresholds and interest rates. Figures reflect the 2026/27 tax year (NRB £325,000, RNRB £175,000, £2,000,000 taper threshold, 40% rate), frozen per HMRC's published rates.