IHT400 Form: England Inheritance Tax Return Explained

The IHT400 is the form that announces to HMRC that an estate is too large or complex to qualify for simplified reporting. It is a 20-page document with up to 20 supplementary schedules, and one in three submissions are rejected or queried on first attempt. If you need to file one, understanding the process before you start saves weeks of delay.

Do You Actually Need an IHT400?

Since January 1, 2022, the simplified IHT205 form was abolished. Simpler estates now report values directly within the HMCTS online probate portal as part of the application. These are called "excepted estates."

An estate qualifies as excepted when:

• The gross estate value is below £325,000 (the nil rate band)
• The gross value is below £650,000 and the entire estate passes to a surviving UK-domiciled spouse or civil partner who did not use any of their own nil rate band
• The gross value is below £3 million and the entirety passes to a UK-domiciled spouse, civil partner, or qualifying charity

If any of those conditions are met, no IHT400 is required. The executor reports estimated values in the online portal and HMCTS processes the probate application directly.

However, even if no inheritance tax is ultimately owed, an IHT400 is required when:

• Foreign assets exceed £100,000
• Trust assets exceed £250,000
• The estate includes business or agricultural property subject to relief
• The deceased had made gifts in the seven years before death that exceeded the annual exemption allowances

Many executors file the IHT205 equivalent thinking their estate is simple, only to discover during estate valuation that a late-discovered foreign bank account or trust pushes them into IHT400 territory. Discovering this after the probate application has been submitted causes HMCTS to stop the application entirely.

The Main IHT400 Form

The IHT400 itself asks for:

• Full details of the deceased (date of death, domicile, whether they made gifts in the last seven years)
• A summary of all assets: property, bank accounts, investments, household contents, vehicles, debts owed to the estate
• A summary of all liabilities: mortgages, loans, credit cards, utility arrears, professional fees
• Inheritance tax calculations: applying the nil rate band, residence nil rate band, and any applicable reliefs

The form must be signed by all acting executors. Where a co-executor has taken Power Reserved, that individual still signs the IHT400 — it is not limited to the acting executor alone.

Supplementary Schedules

The main IHT400 is accompanied by supplementary schedules for specific asset types. You only submit the ones that apply to your estate:

IHT402: Claim to transfer unused nil rate band from a predeceased spouse or civil partner.

IHT403: Details of lifetime gifts made in the seven years before death — including potentially exempt transfers and chargeable transfers.

IHT404: Jointly owned assets (whether held as joint tenants or tenants in common).

IHT405: UK houses, land, and buildings. This is required whenever property is included in the estate. It requests the address, current value, whether it was the deceased's home, outstanding mortgage balance, and the ownership structure.

IHT406: UK bank and building society accounts. Lists each account, the institution, account number, balance at date of death, and whether held jointly.

IHT407: Household goods and personal possessions. Used when the total value of personal chattels exceeds £500.

IHT408: Nominated assets and insurance policies. Used when the deceased named a beneficiary directly on a policy or pension, meaning the asset passes outside the estate.

IHT409: Pensions. Critical for any defined contribution pension pot. Note: from April 6, 2027, unused pension pots will become subject to IHT — currently they sit outside the estate for IHT purposes, but this is changing.

IHT410: Life assurance policies and assets held in trust where the deceased had an interest in possession.

IHT411: Listed stocks, shares, and investments.

IHT416: Debts and liabilities owed to the estate — loans made by the deceased that are outstanding at death.

The most commonly required schedules for a typical English estate are IHT402, IHT405 (if property exists), IHT406, and often IHT403 if the deceased made significant gifts.

The 20-Working-Day Rule

This is the most operationally important rule for executors, and the one most frequently violated.

After you submit the IHT400 to HMRC, you must wait exactly 20 working days before submitting the probate application to HMCTS. The reason is technical: HMCTS and HMRC systems need to synchronise. If you file the probate application before 20 working days have passed from HMRC's acknowledgment, the HMCTS system will find no matching tax record, flag the application as a discrepancy, and move it to the manual review queue — adding 4 to 6 weeks of delay on top of the standard processing time.

HMRC will send an acknowledgment letter when it receives the IHT400. That date is your 20-working-day start point. Count only working days (Monday to Friday, excluding bank holidays). Track the date carefully.

If the estate is straightforward enough to use excepted estate reporting within the probate portal, this 20-day wait does not apply — the values are entered directly into the portal at the time of application.

Paying Inheritance Tax Before Probate

Here is the problem many executors face: inheritance tax must be paid by the end of the sixth month after the date of death to avoid daily interest (currently 7.75% per annum on the unpaid amount). But the banks will not release the deceased's funds without the Grant of Probate, which you cannot get until HMRC has processed your IHT400. The funds needed to pay the tax are locked inside the frozen estate.

There are three ways out of this:

1. Direct Payment Scheme (Form IHT423). Most major banks participate in a scheme where they will transfer funds directly from the deceased's account to HMRC to pay inheritance tax — without probate. You send Form IHT423 to the bank alongside your IHT400, and the bank settles the tax directly. This is the standard solution and is covered in detail in the guide on the IHT423 Direct Payment Scheme.

2. Short-term personal loan or bridging finance. Some executors borrow from family or obtain a short-term bank loan to cover the tax liability, then repay it once the estate is released.

3. Paying by instalments. For certain assets — particularly property and shares in an unlisted company — HMRC permits payment of IHT by annual instalments over ten years. Interest applies, but it can relieve the immediate cash flow pressure while the estate is being administered.

After HMRC Processes the IHT400

HMRC will either:

• Issue a Receipt confirming the IHT400 has been processed and any tax paid (or an instalment schedule confirmed)
• Issue an IHT421 (Probate Summary), which is sent directly to HMCTS to confirm the tax position

The IHT421 used to be issued as a physical document. For online applications, HMRC now transmits it electronically to HMCTS directly — which is another reason the 20-working-day synchronisation window is critical. Wait for confirmation from HMRC before proceeding.

Once the 20 working days have elapsed from HMRC's acknowledgment, submit the probate application. Online via MyHMCTS typically clears in 2–5 weeks for straightforward estates. Paper applications take 13–16 weeks.

The England Probate Process Guide includes a complete IHT400 schedule checklist, the 20-day countdown tracker, and guidance on how to manage the liquidity trap when inheritance tax falls due before probate is granted.

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