The Charity Threshold: Making Sense of the 10% Inheritance Tax Rate

The reduced rate of inheritance tax for charitable estates is one of the more generous-looking rules in the UK tax system. Leave at least 10% of the net estate to charity, and the inheritance tax rate on the rest can fall from 40% to 36%. For a large estate, the saving can be substantial. For a family deciding whether to give away part of an inheritance, however, the arithmetic is rarely as simple as the headline suggests.

The rule is not a discount for any charitable gift. It is a statutory test, and the word net has a technical meaning. A will that leaves 10% of the total estate to charity may overshoot the threshold or, in some circumstances, fail to meet it. Understanding the baseline against which the 10% is measured is essential before treating the reduced rate as a planning tool.

The statutory test in plain terms

In broad terms, the reduced rate applies where the estate leaves at least 10% of the baseline amount to qualifying charities. The baseline is not the probate value of the estate. It is, broadly, the value of the estate for inheritance tax purposes after deducting liabilities, reliefs and exemptions, and after the available nil-rate band and residence nil-rate band, but before the charitable gift itself.

The charitable gift must be to a qualifying charity and must be free of tax. The reduced rate then applies to the rest of the taxable estate. The charity does not pay inheritance tax on its gift, and the estate benefits from a lower rate on the portion that remains taxable.

A simplified calculation

Consider an estate worth £800,000 with no surviving spouse and no residence nil-rate band available. Assume the available nil-rate band is £325,000 and ignore other reliefs for simplicity. The baseline is therefore £475,000. The 10% threshold is £47,500.

Without a charitable gift, inheritance tax at 40% would be £190,000, leaving £610,000 for the family.

With a charitable gift of £47,500, the taxable estate falls to £427,500. Inheritance tax at 36% is £153,900. The family receives £598,600 and the charity receives £47,500. The tax saving is £36,100, but the family is still £11,400 worse off than if no charitable gift had been made. The tax relief softens the cost of the gift; it does not make the family better off.

If the charitable gift is larger, the tax saving grows, but the family’s inheritance still falls. A £100,000 gift in the same estate would produce inheritance tax of £135,000 at 36%, leaving £565,000 for the family and £100,000 for charity. The tax saving is £55,000, but the family has given up more capital. The reduced rate is therefore a question of priorities, not a free lunch.

Where the 10% test goes wrong

The first trap is the word net. Exempt assets do not count in the same way as taxable assets. If half of a £1 million estate passes to a surviving spouse, the baseline is calculated after that exemption and after the available nil-rate band. A will that leaves 10% of the total estate to charity may comfortably exceed the threshold, while a will that leaves 10% of the residue may produce a different result. The wording must match the statutory test.

The second trap is relief. Agricultural property relief and business property relief can reduce the baseline, as can other reliefs. A charitable gift that looks like 10% of the headline estate may be measured against a much smaller taxable amount. Conversely, an estate that includes relievable assets may find that a charitable gift does not produce the expected tax saving because part of the estate was outside the charge anyway.

The third trap is the residence nil-rate band. The family home can add to the available threshold, but the relief tapers away for larger estates. A charitable gift may affect the amount of tax payable, but it does not automatically restore a lost residence nil-rate band. Modelling is required.

The fourth trap is liquidity. If the family home is the main asset, a charitable legacy may require the executors to sell the property or borrow to pay the tax and the gift. That can be especially difficult where the children expect to keep the home. A tax rate is not worth chasing if it undermines the family’s housing security.

The fifth trap is the identity of the charity. Not every organisation qualifies for charitable exemption, and the gift must be structured correctly. Executors will need evidence to claim the reduced rate, and the will should be drafted with the necessary precision.

When the reduced rate genuinely helps

The charitable rate is most straightforward where the deceased genuinely wished to support a charity and the family understands that the gift will reduce their inheritance. In that situation, the 36% rate is a useful additional benefit: the charity receives the intended sum, and the tax saving reduces the cost to the family.

It can also be relevant for estates with no close family, or where the testator wishes to prioritise a cause over distant relatives. For larger estates with a clear charitable intention, the reduced rate can form part of a coherent plan rather than a tax-driven afterthought.

It is less compelling where the estate is below the nil-rate band. If there is no 40% inheritance tax to reduce, a charitable gift does not produce a 36% saving; it simply reduces what the family receives. The same caution applies where the family home is modest and the children have limited housing options. A charitable gift should not be used to chase a rate if it creates hardship or forces a sale.

The family home question

For many UK families, the home is the emotional centre of the estate. If the intention is for children to keep it, a charitable legacy needs careful thought. The gift may be paid from residue, but if the residue is insufficient, the executors may need to sell other assets. In some cases, a smaller charitable gift below the 10% threshold may be the right personal choice, even though it will not unlock the reduced rate. In others, lifetime giving or a different estate structure may be more appropriate.

The key point is that the 10% rule is a tax mechanic, not an estate planning objective. It should be considered alongside the family’s needs, the testator’s charitable intentions and the liquidity of the estate. A plan that reduces the tax rate but leaves the family unable to keep the home is unlikely to be the plan the testator intended.

Practical next steps

In 2026, with pension changes approaching and inheritance tax thresholds under pressure, families should model the charitable option rather than assume it. The calculation should include the baseline amount, the available nil-rate band and residence nil-rate band, reliefs, exemptions and the liquidity of the estate. Executors should also understand the evidence needed to claim the reduced rate.

A charitable legacy can be a powerful way to support a cause and reduce an inheritance tax bill. But the 10% threshold is a technical test with real traps. The right question is not simply whether the estate can meet it, but whether the family and the charity would be better served by meeting it at all.