Filing IHT400: The New Requirement Replacing IHT205 — Complete Guide

IHT205 vs IHT400: What Changed?

Before 2022, many estates used the shorter IHT205 return (for excepted estates with simpler circumstances). Following a recommendation from the Office of Tax Simplification, HMRC abolished IHT205 for deaths on or after 1 January 2022. The excepted estate rules were updated and extended instead, so more estates fall outside the need for any IHT account at all, while those that do file must use IHT400.

The key change: estates that previously used IHT205 but were not truly "excepted" must now file IHT400 instead. HMRC estimated this change would affect approximately 240,000 estates per year.

Do You Need to File IHT400? Excepted Estates Explained

You do not need to file IHT400 if the estate qualifies as an "excepted estate." Since January 2022, the excepted estate rules are:

If the estate qualifies as excepted, you confirm this on the PA1P or PA1A probate application form instead of filing IHT400. No IHT return is needed, but you still need to apply for probate if one is required.

IHT400: The Main Form

IHT400 is a 16-page main form covering:

• Details of the deceased and the person filing (the "liable person").
• Summary of all assets at the date of death.
• Summary of all liabilities (debts, mortgages, expenses).
• Gifts made in the 7 years before death.
• Trusts and settled property.
• Exemptions and reliefs being claimed (e.g. spouse exemption, BPR, RNRB).
• IHT calculation — tax payable and instalments if applicable.

The main form directs you to complete relevant supplementary schedules for different asset types. You only complete the schedules applicable to your estate.

Key IHT400 Supplementary Schedules

Deadline and Payment

IHT400 must be submitted, and the IHT due paid, within 6 months of the date of death. After this point, HMRC charges interest on unpaid IHT (currently at the HMRC interest rate, which can be significant). For more on the cost of delays, see our guide to probate delays and IHT interest.

A common challenge is that you must pay IHT before you can obtain probate — but you cannot access estate funds to pay it without probate. The solution is the Direct Payment Scheme, which allows HMRC to collect IHT directly from the deceased's bank accounts. See our guide to paying IHT before probate.

IHT on certain assets (primarily property) can be paid by instalments over 10 years. Interest applies from the 6-month deadline on unpaid instalments.

The IHT Reference Number

Before submitting IHT400, you must obtain an IHT reference number from HMRC. Apply online via HMRC's IHT portal or by calling HMRC. Once IHT400 is processed, HMRC issues a receipt (IHT421) confirming the estate's IHT position. This receipt is required when applying for probate.

Common Mistakes in IHT400

• Failing to include all assets — check pension death benefits (if paid to estate), life insurance not written in trust, and foreign assets.
• Using insurance values for jewellery instead of open market values — see our guide to valuing jewellery and art.
• Missing gifts made in the 7 years before death — these must be reported in Schedule IHT403.
• Failing to claim all available reliefs — particularly the transferable nil-rate band (IHT402) and RNRB (IHT435/IHT436).
• Not deducting all liabilities — funeral expenses, debts, and administration costs can all reduce the taxable estate.

For the full IHT calculation and reliefs available, see our inheritance tax guide for 2026–27. For probate application after IHT400 is submitted, see our guide to PA1P vs PA1A probate application forms. Use our free estate administration tool to build a personalised task list.

Related Guides

• Paying IHT Before Probate
• Valuing a Property for Probate
• Transferring the Nil Rate Band Between Spouses
• Executor First Steps
• Complete UK Probate Guide 2026