Inheritance tax can become one of the largest liabilities an estate ever faces.
Yet many families have never calculated what their potential inheritance tax bill might actually be.
They may know that inheritance tax is charged at 40%, but that does not necessarily mean 40% of the entire estate will be paid to HMRC.
The calculation depends on the value of the estate, the allowances available, who inherits the assets and how the estate has been structured.
Understanding the potential liability is therefore an important starting point for inheritance tax planning.
How Is Inheritance Tax Calculated?
For many estates, inheritance tax is charged at 40% on the value above the available tax-free allowances.
The standard nil-rate band is currently £325,000 per person.
There may also be a residence nil-rate band of up to £175,000 per person when a qualifying home is passed to direct descendants, subject to the relevant conditions.
For married couples and civil partners, unused allowances may potentially be transferred to the surviving spouse or civil partner.
This means that, in the right circumstances, a couple may eventually have combined allowances of up to £1 million.
But this figure should not simply be assumed.
The £1 Million Allowance Is Not Available to Everyone
One of the most common misunderstandings in inheritance tax planning is that every married couple automatically has a £1 million tax-free estate.
They do not.
The residence nil-rate band comes with conditions and begins to taper away for estates worth more than £2 million.
For every £2 by which the estate exceeds the £2 million threshold, £1 of residence nil-rate band is lost.
This can make a significant difference to larger estates.
An estate that appears to be only moderately above £2 million can therefore find itself facing a substantially larger inheritance tax liability than the family expected.
A Simple Example
Imagine a married couple whose combined estate is worth £1.5 million.
If the full £1 million of combined allowances were ultimately available, approximately £500,000 could remain exposed to inheritance tax.
At 40%, that could mean an inheritance tax liability of around:
£200,000
Now consider an estate worth £2.5 million.
The calculation becomes more complicated because the residence nil-rate band may be reduced or lost.
The potential inheritance tax liability can therefore rise much faster than many families expect.
And the size of the estate today is only part of the calculation.
Your Estate May Continue Growing
Inheritance tax is generally a liability calculated on the estate at death, not on what the estate was worth when you first started planning.
Property may appreciate.
Investments may grow.
Businesses may become more valuable.
Cash and other assets may accumulate.
And from 6 April 2027, most unused pension funds and death benefits are due to be brought within the inheritance tax regime, subject to the legislation and applicable exemptions.
For some families, pensions that previously sat outside their inheritance tax calculations may therefore become an important part of the estate-planning picture.
This is why simply calculating today’s inheritance tax liability may not be enough.
The more useful question is:
What could the estate — and the potential tax liability — look like in five, ten or twenty years?
A Growing Estate Can Mean a Growing Tax Bill
Consider an estate worth £1.5 million today.
If its assets continue increasing in value over a long period, the eventual estate could be considerably larger.
Meanwhile, the main inheritance tax thresholds are currently frozen until 5 April 2031.
That combination matters.
If asset values rise while allowances remain unchanged, a greater proportion of the estate may potentially become exposed to inheritance tax.
This is sometimes referred to as fiscal drag.
Families can therefore find themselves facing a larger inheritance tax problem without making any dramatic changes to their finances.
Inheritance Tax Planning Is Not Just About Giving Money Away
There is another misconception worth addressing.
Reducing an inheritance tax liability does not necessarily mean giving away everything you own.
Good estate planning should also consider:
your financial security and lifestyle;
how much control you want to retain;
property ownership;
pensions and investments;
family circumstances;
liquidity available to the executors;
existing wills, trusts and beneficiary arrangements; and
how the different parts of the estate work together.
The objective should not simply be to create the smallest possible estate.
It should be to understand the potential liability and consider whether the estate could be structured more effectively while protecting the owner’s own financial position.
Start With the Number
Before deciding whether inheritance tax planning is necessary, establish what the potential problem actually is.
What is your estate worth today?
Which allowances are likely to be available?
Could the residence nil-rate band be reduced or lost?
How might your estate change over time?
What effect could the April 2027 pension changes have?
And, ultimately:
How much could your family actually have to pay?
Once those numbers are understood, it becomes much easier to decide whether further planning deserves consideration.
Do You Know Your Potential Inheritance Tax Bill?
Many families know inheritance tax is charged at 40%, but have never calculated what that could mean for their own estate.
Understanding your potential liability is the starting point for deciding whether further planning deserves consideration.