Form IHT400: Full Inheritance Tax Account (2026 Guide)

Form IHT400 is the full inheritance tax account required by HMRC when an estate exceeds the nil-rate band, holds complex assets, or triggers reporting rules that the shorter IHT205 route cannot cover. It sits at the heart of any non-excepted estate in England and Wales, and it must be filed before probate can be granted on anything but the simplest cases. The form is long, the schedules are many, and the six-month payment clock starts ticking from the end of the month of death whether you are ready or not. This guide walks you through every box, every schedule, every deadline — and shows you how Chris drafts the whole return to HMRC standard in a single afternoon. Build your case with Chris. Prepare to win, plan not to fail.

When Do You Need Form IHT400?

IHT400 is the full return. You need it wherever the estate cannot be classified as an excepted estate under the Inheritance Tax (Delivery of Accounts) (Excepted Estates) (Amendment) Regulations 2021. In practice this means any of the following trigger it:

• The gross value of the estate exceeds the nil-rate band of £325,000, and the full spouse exemption does not wipe the liability to nil.
• The deceased made non-exempt lifetime gifts in the seven years before death exceeding £250,000.
• The estate includes business relief or agricultural relief assets (farms, trading companies, AIM shares qualifying for BR).
• There are foreign assets worth more than £100,000, or the deceased was domiciled outside the UK.
• The deceased held an interest in a trust worth more than £250,000.
• You wish to claim the transferable nil-rate band or residence nil-rate band from a predeceased spouse.
• The estate includes complex assets — life assurance written outside trust, alternatively secured pensions, gifts with reservation of benefit.

If none of those apply and the estate is under £325,000, you will usually file IHT205 (or, since January 2022, simply declare the estate values on the probate application itself). If in doubt, file IHT400. The court will expect a properly supported return, and so will HMRC.

What Form IHT400 Involves

IHT400 is a 16-page master form supported by up to 20 schedules. The master form lists the deceased’s personal details, domicile, will or intestacy status, and totals every asset and liability across the schedules. The schedules carry the detail — each one devoted to a specific asset class or relief. You complete only the schedules your estate touches, but you must complete them fully. HMRC cross-references every figure against probate valuations, bank statements, and Land Registry records. Omissions invite enquiry. Enquiries delay probate by months.

The return also determines the IHT liability, which must be paid (in full or by instalments on qualifying property) before HMRC issues the IHT421 probate summary. Without IHT421, the Probate Registry will not grant probate on your PA1P or PA1A application. The forms are interlocking: IHT first, probate second.

Fees and Costs

There is no fee to file IHT400. HMRC does not charge for processing an inheritance tax return. The costs that bite are the tax itself and the probate fee that follows.

• Inheritance tax rate: 40% on the net estate above the nil-rate bands.
• Reduced rate: 36% where 10% or more of the net estate is left to charity (Sch 1A IHTA 1984).
• Payment deadline: six months from the end of the month of death. Interest accrues daily from that date at HMRC’s statutory rate (currently 7.75%).
• Instalment option: tax on land, buildings, and certain business/unlisted shares may be paid in ten equal annual instalments (s.227 IHTA 1984).
• Probate fee (England & Wales): £300 for estates over £5,000. £1.50 per additional sealed copy.

How to Complete Form IHT400 — Step by Step

Work through the master form, then the schedules, then return to the summary. Do not try to complete it linearly — gather the valuations first, complete each schedule, then carry the totals back to IHT400.

Step 1 — Obtain an IHT reference number (IHT422)

You cannot pay inheritance tax without a reference number. File Form IHT422 at least three weeks before you expect to pay. The reference arrives by post. Without it, banks will not release funds under the Direct Payment Scheme and HMRC cannot allocate your payment correctly.

Step 2 — Master form: pages 1-8 (personal and domicile details)

Boxes 1-22 cover the deceased’s name, date of death, NI number, occupation, domicile, and will status. Boxes 23-28 cover the spouse or civil partner and the question of survivorship. Boxes 29-49 identify every beneficiary, executor, and their relationship to the deceased. Accuracy here prevents downstream queries.

Step 3 — Schedule IHT402 — Transferable nil-rate band

If the first spouse to die did not use their full NRB, the survivor’s estate can claim the unused percentage. You must file IHT402 with evidence of the first death. There is a two-year deadline from the second death to claim the transferable NRB. Miss it and the relief is lost.

Step 4 — Schedule IHT403 — Gifts and lifetime transfers

List every gift over £250 made in the seven years before death. Apply taper relief where appropriate (s.7(4) IHTA 1984). Identify gifts with reservation of benefit — these come back into the estate at the date of death value, not the date of gift.

Step 5 — Schedules for land, bank, and household

IHT405 — each property, with professional RICS valuation where possible. IHT406 — every bank and building society account with closing balance and interest to date of death. IHT407 — household goods, cars, jewellery, and chattels.

Step 6 — Schedules for pensions and life policies

IHT409 — occupational, personal, and annuity pensions. IHT410 — life assurance policies. Policies written into trust usually fall outside the estate but must still be disclosed.

Step 7 — Schedules for shares and investments

IHT411 — listed stocks and shares at mid-market quotation on the date of death (the quarter-up rule). IHT412 — unlisted and AIM shares with professional valuation.

Step 8 — Schedules for reliefs

IHT413 — business relief (100% on trading businesses and unquoted shares held for two years, 50% on certain assets). IHT414 — agricultural relief on farmland and farmhouses occupied for the qualifying period.

Step 9 — Schedules for trusts and debts

IHT418 — any interest the deceased held in a trust. IHT419 — debts owed to close family, loans, and liabilities that reduce the net estate. HMRC scrutinises family debts closely under s.175A IHTA 1984.

Step 10 — Residence nil-rate band (IHT435 and IHT436)

IHT435 claims the £175,000 RNRB where a qualifying residential interest is closely inherited by direct descendants. IHT436 claims the transferable RNRB from a predeceased spouse. Combined with the transferable NRB, a surviving spouse’s estate can pass up to £1,000,000 free of IHT. The RNRB tapers by £1 for every £2 above the £2 million estate threshold.

Step 11 — Direct Payment Scheme (IHT423)

If the estate has insufficient liquid funds to meet the six-month deadline, IHT423 authorises banks and building societies to transfer funds directly to HMRC from the deceased’s accounts. Send one IHT423 per institution, each with the IHT reference.

Step 12 — IHT421 probate summary

Once HMRC receives IHT400, the tax is paid (or first instalment paid), and any enquiries are satisfied, HMRC issues IHT421 directly to the Probate Registry. You can then progress your PA1P or PA1A application. Allow 20 working days minimum between IHT400 submission and probate application.

Key Deadlines

• 12 months from end of month of death — deadline to deliver IHT400 to HMRC (s.216 IHTA 1984).
• 6 months from end of month of death — deadline to pay IHT. Interest accrues from this date.
• 2 years from date of death — deadline to execute a deed of variation redirecting inheritances (s.142 IHTA 1984).
• 2 years from second death — deadline to claim transferable RNRB on IHT436.
• 4 years — HMRC’s standard window to open an enquiry into a filed return.
• 10 years — maximum instalment period for qualifying property and business assets.

What Happens After You File

HMRC acknowledges receipt within two to four weeks and begins its risk-assessment review. If the return is clean, HMRC issues a calculation and requests payment of the balance. Once tax is cleared, IHT421 goes to the Probate Registry within a further two to six weeks. If HMRC opens an enquiry — common where business or agricultural relief is claimed, or where property valuations are contentious — expect a District Valuer referral and a delay of three to nine months.

After probate is granted, the executors distribute the estate. If further assets surface, you file a C4 Corrective Account within six months of discovery.

Common Mistakes to Avoid

• Filing IHT400 before obtaining the IHT422 reference. HMRC cannot allocate your payment and interest runs in the meantime.
• Missing the two-year RNRB transfer window. The relief is lost forever — worth up to £70,000 in tax.
• Under-valuing property. The District Valuer will challenge anything that looks low. Get a RICS Red Book valuation for anything over £500,000.
• Forgetting failed PETs. Gifts within seven years of death come back into the estate. Banking records are discoverable.
• Claiming business relief on investment companies. Companies whose main activity is holding investments do not qualify under s.105(3) IHTA 1984.
• Paying IHT from estate funds before probate without using IHT423. Banks will usually refuse — and you personally cannot access the funds yet.

The Rules That Apply

The primary statute is the Inheritance Tax Act 1984. Key sections:

• s.1-3 — charge to tax and transfers of value
• s.7 and Sch 1 — rates of tax, taper relief, and the reduced charity rate (Sch 1A)
• s.8A-8M — transferable nil-rate band and residence nil-rate band
• s.18 — spouse exemption
• s.104-114 — business relief
• s.115-124C — agricultural relief
• s.216 — duty to deliver accounts
• s.226-228 — payment and instalment option
• s.142 — deeds of variation

How Chris Can Help

IHT400 is the kind of form where accuracy is everything and the penalty for getting it wrong is paid in months, not pounds. Chris drafts the full return — master form, every schedule, IHT421 summary, and the IHT423 direct payment authorities — to the standard HMRC expects. You provide the valuations, the bank statements, the will, the list of gifts. Chris turns it into a clean, complete, cross-referenced return in an afternoon. You check it, sign it, and file it. The court and HMRC see a properly supported account.

7-day money-back guarantee. Not happy with the draft before you sign and send? We refund. We would rather refund an unhappy customer than send a return that isn’t ready. We are miracle-makers, not miracle-workers — if the underlying estate is messy, no drafting hides it. Chris makes strong returns stronger. Chris cannot make bad valuations good.

When the person behind eLitigant navigated their own family probate, a solicitor quoted £1,200 and took two years without resolution. Sitting down with Chris for an afternoon, the forms were drafted, the estate closed in three weeks. Most solicitors are excellent — but access to justice should not depend on finding the right one. That is why Chris exists.

Subscribe for our application: Email hello@elitigant.com with subject line “Application update” and say hello with your given name.

Complex estate — farmland, a family company, trusts, foreign assets? That is exactly where Hybrid (£1,000) earns its keep: concierge drafting with qualified reviewer sign-off before you file. Straightforward estate under £2m with a home and a few accounts? Litigator (£30) is you.

Frequently Asked Questions

Do I need IHT400 if everything passes to my spouse?

Often no — if the spouse exemption reduces the liability to nil and the estate meets the excepted estate rules, you can avoid IHT400. But if you want to claim the transferable NRB or RNRB for the surviving spouse’s future estate, filing IHT400 now preserves the paper trail.

What is the nil-rate band in 2026?

£325,000, frozen until April 2028. The residence nil-rate band adds up to £175,000 where a qualifying residence passes to direct descendants.

Can I pay inheritance tax in instalments?

Yes — on land, buildings, controlling shareholdings, certain unlisted shares, and qualifying business assets. Ten equal annual instalments under s.227 IHTA 1984.

What happens if I miss the six-month payment deadline?

Interest accrues daily at HMRC’s statutory rate. The 12-month delivery deadline carries penalties up to £3,000 plus daily penalties under s.245 IHTA 1984.

Can I file IHT400 myself?

Yes. There is no requirement to use a solicitor. What matters is that every figure is accurate, every schedule is complete, and every relief is properly supported. Chris drafts to that standard and you file it yourself.

What is a deed of variation?

A deed of variation under s.142 IHTA 1984 lets beneficiaries redirect their inheritance and have the variation treated for IHT as if the deceased had made the gift. Must be executed within two years of death.

How long does HMRC take to process IHT400?

Clean returns are typically processed within four to eight weeks. Returns claiming business relief, agricultural relief, or contested valuations can take three to nine months.