When someone passes away, sorting out their estate comes with important tax deadlines that cannot be ignored. Each year, HMRC collects over £7 billion in Inheritance Tax, showing just how significant this tax is across the UK. Miss a deadline, and the penalties and interest charges start adding up fast.
The rules apply even when no tax is actually owed, which surprises a lot of families. Getting the dates right, knowing what HMRC expects, and understanding what happens when things go wrong can save the estate a lot of money.
When someone dies, the people managing their estate need to act quickly. The main IHT payment deadline is six months after the end of the month in which the person died. So if someone passed away in March, the tax would need to be paid by 30 September that same year.
The form used to report the estate to HMRC is called the IHT400. This must usually be sent within 12 months of the date of death. It is worth knowing that the payment deadline and the filing deadline are not the same thing. HMRC expects the tax to be paid before probate is granted, which means payment often needs to happen while the estate is still being sorted out.
Key dates to remember:
According to HMRC’s Inheritance Tax guidance, executors can sometimes pay IHT in instalments, especially when the estate includes property or land. But interest still builds up on any unpaid amounts from the due date, even if instalments have been agreed.
If the estate includes property, understanding how IHT and other taxes connect is important. ETC Tax’s property tax team can help families work through these situations. For broader estate and IHT planning, the private client tax service covers the full picture from start to finish.
Missing the IHT return deadline penalty is something many families only learn about after it has already happened. HMRC applies fixed penalties for late IHT400 submissions, but these are capped by the amount of tax due. The government website says the late-account penalties are limited to the amount of tax due, and if the tax due is later reduced to nil, the penalty should be repaid.
The penalty structure works like this:
In the most serious cases, such as deliberate non-compliance, the tax-related penalty can reach up to 100% of the unpaid tax. For most executors who simply fell behind because the estate was complicated, the penalties are lower but still add unnecessary cost to the process.
It is also important to know that penalties are separate from interest. Missing the deadline means the estate could face both at the same time, which can be a significant financial burden for beneficiaries.
What to do if you have already missed the deadline:
ETC Tax’s private client tax team helps executors manage IHT obligations and avoid unnecessary penalties. If HMRC has already raised a penalty, the tax disputes and investigations team can step in to help.
Interest on late IHT payments is charged separately from penalties and starts building the day after the payment deadline passes. HMRC links its late payment interest rate to the Bank of England base rate. As of 2024, this rate has been sitting at around 7.75%, but it can change whenever the base rate moves.
How the interest works:
For large estates where the IHT bill is significant, even a short delay can result in a meaningful amount of extra cost. A few months of interest on a £500,000 tax bill, for example, adds up quickly.
There is also a situation where interest works in the executor’s favour. If the estate’s value drops after death, for instance, if a property is sold for less than its probate value, a refund of IHT may be due. In that case, HMRC pays interest back to the estate.
Understanding the full cost of a late payment is part of managing an estate well. ETC Tax’s private client tax service helps executors plan ahead so interest charges do not catch the estate off guard. Where an estate involves property that may be sold at a loss, the property tax team can advise on what happens next.
Not every estate needs to submit a full IHT return, but it is important not to assume. Even estates that do not owe any Inheritance Tax may still need to file one, depending on the size and makeup of the estate.
An estate usually needs to file an IHT400 if:
For deaths before 1 January 2022, a shorter form called the IHT205 was used for smaller estates. This has now been replaced, and most estates are reported through the probate process instead.
What makes an estate more complex?
According to HMRC’s Inheritance Tax guidance, getting the valuation of these assets right is critical, as errors can lead to penalties or delays in obtaining probate.
If the estate includes property that is later sold, there may also be Capital Gains Tax to consider. ETC Tax’s property tax team can advise on how both taxes interact during estate administration. For estates with digital assets, the crypto tax service can help work out how these should be valued and reported.
The IHT return deadline penalty can catch even careful executors off guard. Estate administration takes time, and several common situations can cause delays that push the filing past the deadline without anyone realising.
The most common reasons include:
When beneficiaries cannot agree on how the estate should be handled, it slows everything down. Gathering the financial information needed to complete the IHT400 becomes much harder when there is conflict between family members.
Properties, business interests, and investments all need to be formally valued. This can take weeks or even months, especially in a slow market or when specialist valuers are needed.
Most executors are family members, not tax professionals. Many do not realise that IHT obligations exist even when no tax is owed. HMRC’s forms can feel confusing, and without support, it is easy to miss important steps.
Estates that include overseas property, foreign accounts, or cryptocurrency take much longer to sort out. Values need to be confirmed in different currencies, and different rules may apply depending on where the assets are held.
According to HMRC guidance, all of these situations still require timely filing, regardless of the complexity involved.
ETC Tax’s private client tax team supports executors through every stage of the process. For estates with cryptocurrency or other digital assets, the crypto tax team can advise on how to handle reporting correctly and on time.
If the IHT return deadline has been missed, it does not mean the full penalty is unavoidable. HMRC does allow executors to appeal penalties in certain situations, and acting quickly can limit the damage.
Steps to take if you have missed the deadline:
What counts as a reasonable excuse?
HMRC accepts reasonable excuse claims where something unexpected made it impossible to file on time. Examples that have been accepted include:
It is important to note that HMRC will not accept general busyness or lack of knowledge as a reasonable excuse. The grounds need to be specific and supported by evidence. According to HMRC’s penalty guidance, appeals that are vague or unsupported are regularly rejected.
ETC Tax’s tax disputes and investigations team handles HMRC appeals and can help build a strong case. For broader IHT planning and compliance support, the private client tax service is available to help executors stay on track from the start.
Sorting out a loved one’s estate is hard enough without worrying about penalties and missed deadlines. The rules around IHT reporting can be confusing, and a small mistake can end up costing the estate a lot of money.
ETC Tax helps families, executors, and estate administrators across the UK get it right. From working out what needs to be filed and when, to dealing with HMRC if something has already gone wrong, the team makes the process easier to manage.
If the estate involves property, overseas assets, or anything complicated, early advice makes a real difference. Reach out to the private client tax team or head to the contact page to talk to someone who can help. If HMRC has already raised a penalty, the tax disputes and investigations team is ready to step in.
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