The IHT400 Form

Key facts

The IHT400 is required when the estate does not qualify as an excepted estate.
It must be submitted to HMRC within 12 months of the end of the month of death (but IHT payment is due at 6 months).
The form includes a series of supplementary schedules (IHT401–IHT423) covering specific asset types and reliefs.
HMRC processes the IHT400 and issues a receipt (IHT421) that is needed for the probate application.
Penalties apply for late submission, inaccuracies, or failure to disclose assets.

What Is the IHT400?

The IHT400 is the full Inheritance Tax account — a detailed return submitted to HMRC by the personal representatives of an estate. It sets out the deceased’s assets, liabilities, lifetime gifts, exemptions claimed, and reliefs applied, enabling HMRC to calculate the IHT due.^[1]

An IHT400 must be submitted when the estate does not qualify as an excepted estate. For excepted estates, the IHT information is included in the probate application instead.

When Is an IHT400 Required?

You must submit an IHT400 if any of the following apply:^[2]

The gross value of the estate exceeds the available IHT threshold (NRB plus any transferable NRB)
The deceased made gifts exceeding £250,000 in the 7 years before death
The estate includes trust assets in which the deceased had a qualifying interest
The estate includes foreign assets worth more than £100,000
A claim is being made for BPR or APR that takes the estate below the threshold
The estate does not otherwise meet the excepted estate conditions

Key Supplementary Schedules

The IHT400 is accompanied by supplementary schedules, each covering a specific area:^[1]

Schedule	Covers	When Required
IHT401	Domicile outside England and Wales	Non-domiciled deceased
IHT402	Transferable nil-rate band claim	Claiming unused NRB from a predeceased spouse
IHT403	Gifts and other transfers	Gifts made in 7 years before death
IHT404	Jointly owned assets	Any jointly held property or accounts
IHT405	Houses, land, buildings, and interests in land	Estate includes property
IHT406	Bank and building society accounts	Estate includes bank accounts
IHT409	Pensions	Estate includes pension benefits
IHT411	Listed stocks and shares	Estate includes quoted investments
IHT413	Business and partnership interests (BPR/APR)	Claiming BPR or APR
IHT417	Foreign assets	Estate includes overseas assets
IHT418	Assets held in trust	Deceased had interest in settled property
IHT423	Direct Payment Scheme	Paying IHT from the deceased’s accounts

Key point: You only need to complete the schedules relevant to the estate. The IHT400 guidance notes explain which schedules to include. Most estates will require IHT404 (joint assets), IHT405 (property), and IHT406 (bank accounts) at a minimum.

Deadlines and Penalties

The IHT400 has two important deadlines:^[2]

Payment deadline: IHT is due 6 months from the end of the month of death. Interest is charged from this date on any unpaid tax.
Filing deadline: The IHT400 must be submitted within 12 months of the end of the month of death. Penalties apply for late filing.

In practice, most executors submit the IHT400 and pay the tax at the same time, typically within 4–6 months of death, to obtain the IHT421 receipt needed for the probate application.

Tips for Completing the IHT400

Obtain professional valuations for property, businesses, and valuable personal possessions
Use date-of-death values for all assets (not probate or sale values)
Include all assets worldwide — failure to disclose can result in penalties
Claim all available exemptions and reliefs (NRB, RNRB, spouse exemption, BPR, APR, charity exemption)
Keep evidence and supporting documents for at least 20 years (HMRC can enquire for this period for IHT)

Correcting errors: If you discover an error after submitting the IHT400, you should write to HMRC with the correction as soon as possible. HMRC may issue a “corrective account” form (C4). Penalties for inaccuracies are lower if you disclose the error voluntarily.

Frequently Asked Questions

When do I need to file an IHT400?

You must file an IHT400 when the estate does not qualify as an excepted estate. This typically means the gross estate exceeds the nil-rate band (including any transferable NRB), the estate includes foreign assets above £100,000, or certain trusts or lifetime gifts are involved.

How long do I have to submit the IHT400?

The IHT400 must be submitted within 12 months of the end of the month of death. However, the IHT payment deadline is earlier — 6 months from the end of the month of death. In practice, most people submit the IHT400 and pay the tax at the same time, well within the 12-month deadline.

What schedules do I need to include?

The specific schedules depend on the estate. Common ones include IHT403 (gifts), IHT404 (jointly owned assets), IHT405 (houses and land), IHT406 (bank accounts), IHT409 (pensions), IHT411 (listed shares), IHT413 (BPR/APR), IHT417 (foreign assets), and IHT418 (assets held in trust).

Can I submit the IHT400 online?

The IHT400 can be completed and submitted online through HMRC’s service. Alternatively, it can be completed as a paper form and posted to HMRC. The online service is generally faster and allows tracking of the submission.

Sources

Inheritance Tax account (IHT400) — GOV.UK
IHTM05000 – Delivery of accounts — HMRC
How to value an estate for Inheritance Tax — GOV.UK