The IHT400 is HMRC's full inheritance tax return, required for any estate that doesn't qualify as "excepted".
It comes with supplementary schedules (IHT401 to IHT436) covering everything from jointly owned assets to foreign property to charity relief.
Below: the 9 schedules most filers actually encounter, what each is for, and the traps that cause penalties.
Current official HMRC documents
Open the form and notes before choosing schedules
HMRC's current English IHT400 form is the April 2026 edition. The form cannot save a partly completed session, so use the notes to gather the estate information first.
Confirm the estate actually needs IHT400 — many small / simple estates (and larger ones passing wholly to a spouse or charity) qualify as "excepted" and report their value directly on the probate application instead.
Apply for an IHT reference (IHT422) online before submitting IHT400 if you'll owe tax.
Estimate the liability first with the Inheritance Tax Calculator, then use the official IHT400 calculation pages and schedules for the filed figures.
IHT is due 6 months after the end of the month of death. Interest accrues beyond that — you can pay before filing IHT400.
IHT400 — Main inheritance tax account
When to use
Required for any estate NOT qualifying as an 'excepted estate'. Broadly: gross value exceeds the available NRB (£325k, or £3,000,000 if it passes wholly to a spouse/civil partner/charity), foreign assets over £100,000, more than one trust or trust assets over £250,000 (a higher limit applies where trust assets pass to a surviving spouse, civil partner or charity), or lifetime gifts over £250,000 in the 7 years before death.
What it does
Running total of all estate assets and debts, the final IHT calculation, and a summary of which schedules apply. Submit to HMRC within 12 months of the end of the month of death (or 3 months after the executors first act, if that is later); interest accrues on unpaid IHT from month 6.
Watch out for
Do NOT complete if the estate is an 'excepted estate' — for deaths on or after 1 January 2022 there is no separate paper form: report the estate's gross/net value directly on the probate application (PA1P/PA1A). The old standalone IHT205 form was abolished from that date.
Sections divide into Assets (A–L), Debts (M), Gifts (N), Working Sheets (P1–P14).
The final IHT figure on IHT400 is what goes on the IHT421 probate summary.
IHT402 — Claim to transfer unused nil rate band
When to use
Surviving spouse or civil partner dies and the first spouse's NRB was partially or fully unused.
What it does
Calculates the percentage of NRB unused on the first death and applies it to the survivor's estate. Up to 100% can transfer, doubling the survivor's NRB to £650,000 (plus doubled RNRB of £350,000 if main home passes to descendants).
Watch out for
You need the first spouse's IHT figures or the date-of-first-death estate valuation.
The unused percentage is worked out against the nil rate band in force when the first spouse or civil partner died, then applied to the band in force at the second death. The survivor must have died on or after 9 October 2007.
Civil partners (post-Dec 2005) and same-sex married couples get full transferability.
IHT403 — Gifts and other transfers of value
When to use
The deceased made gifts, transfers, or set up trusts within 7 years of death (including Potentially Exempt Transfers and Chargeable Lifetime Transfers).
What it does
Lists each gift with date, recipient, value, and exemptions claimed (£3,000 annual, £250 small gifts, wedding gifts, gifts from surplus income). HMRC applies the 7-year taper: gifts within 3 years = full 40%, then sliding to 0% at 7+ years.
Watch out for
Gifts consume NRB in DATE ORDER (oldest first) before any remaining NRB flows to the estate.
Taper reduces the TAX, not the gift value — and only matters when the gift exceeds available NRB.
Tell HMRC about any gifts the deceased made on or after 18 March 1986 on IHT403, sent with the IHT400, so ask beneficiaries and family what they were given.
Gifts with reservation of benefit (e.g., giving away a house but continuing to live in it rent-free) are treated as still in the estate.
IHT404 — Jointly owned assets
When to use
The deceased held assets jointly (bank accounts, property, investments) with another person.
What it does
Declare the deceased's proportionate share. For beneficial joint tenants: assume equal shares unless evidence otherwise. For tenants in common: use the stated shares in the deed.
Watch out for
A joint bank account with a spouse usually passes by survivorship — but the deceased's share still counts in the IHT estate.
If the non-deceased owner contributed nothing, HMRC may challenge the 50/50 presumption.
IHT405 — Houses, land, buildings and interests in land
When to use
The estate includes real property.
What it does
Lists each property with address, tenure (freehold/leasehold), valuation at date of death, outstanding mortgage, and intended beneficiary. The sum flows into the main IHT400 assets total.
Watch out for
Get the property valued by an estate agent or chartered surveyor. HMRC's Valuation Office may check the figure and, if it decides the asset is worth more, HMRC will send new calculations.
The RNRB only applies to the deceased's main residence (not buy-to-let), and only if it passes to direct descendants.
If the deceased downsized or sold their home before death, a downsizing addition may still preserve some of the RNRB — claim it on the RNRB schedule, IHT435, not on IHT405.
IHT411 / IHT412 — Listed / unlisted stocks and shares
When to use
The estate holds any shares, bonds, or securities.
What it does
Listed shares (IHT411): value at date of death using the 'quarter-up' rule (lower of two published prices + 1/4 of the difference). Unlisted (IHT412): requires a formal valuation, often from a specialist accountant.
Watch out for
AIM shares qualifying for Business Relief get 100% relief for deaths before 6 April 2026, or 50% relief for deaths on or after 6 April 2026 — list the shares on IHT412 (unlisted stocks and shares), not IHT411.
Include accrued dividends declared before death but paid after.
IHT419 — Debts owed by the deceased
When to use
The deceased had outstanding loans, credit cards, or personal debts at death.
What it does
Lists each debt so it can be deducted from the gross estate. Include mortgage balances (if not already offset in IHT405), utility arrears, and informal family loans.
Watch out for
Informal loans from family are scrutinised — provide written evidence of the loan at inception.
Debts specifically charged against exempt assets (e.g., mortgage on charity-left property) don't reduce the taxable estate.
IHT421 — Probate summary for Northern Ireland
When to use
Used for a probate application in Northern Ireland. England and Wales now use the HMRC unique probate reference code instead of sending IHT421 with the probate application.
What it does
Summarises the gross estate, net estate, IHT payable and payments for the Northern Ireland probate process. Follow the current jurisdiction-specific instructions before submitting it.
Watch out for
IHT must be paid (or first instalment on property/shares) BEFORE probate is granted — use the Direct Payment Scheme (IHT423) to pay IHT directly from the deceased's bank.
For England and Wales, wait for HMRC's unique code before completing the probate application; do not use the Northern Ireland IHT421 route.
IHT430 — Reduced rate of inheritance tax (charity)
When to use
The estate leaves at least 10% of the 'baseline amount' to qualifying charities.
What it does
Calculates the charity threshold and confirms the reduced 36% rate applies. The baseline amount is broadly the net estate after spouse/civil partner exemption minus the available NRB.
Watch out for
Run the numbers both ways — sometimes increasing a charity gift to hit 10% saves more IHT than the extra gift costs.
The reduced rate applies to the component (free estate, joint property, trust) that meets the 10% test — not automatically to the whole estate.
Gift taper relief bands (IHT403 reference)
Taper reduces the IHT on pre-death gifts that exceed the NRB. All figures from the Inheritance Tax Act 1984 s7 and HMRC IHTM14611.
No — many estates qualify as an "excepted estate" and skip IHT400 entirely. Two main categories: a "low value" excepted estate (gross value under the available NRB — £325,000, or £650,000 with a full transferable NRB), or an "exempt" excepted estate (gross value up to £3,000,000 where the amount passing to a spouse/civil partner/charity brings the net chargeable value at or below the available NRB). Both categories also require: foreign assets of no more than £100,000, any trust assets held in a single trust worth no more than £250,000 (a higher limit applies where the trust passes to a surviving spouse, civil partner or charity), and lifetime gifts of no more than £250,000 in the 7 years before death. For deaths on or after 1 January 2022, excepted estates report their value directly on the probate application (PA1P/PA1A) — the old standalone IHT205 form no longer exists. Estates that miss any of these tests, or have more complex features (multiple trusts, foreign domicile, gifts with reservation of benefit), need the full IHT400.
When is IHT payable?
IHT is due 6 months after the end of the month of death. For example, death on 10 May means IHT is due by 30 November. Interest accrues on unpaid tax from the 6-month point. IHT on land and buildings, certain shares and business or agricultural property can be paid in 10 annual instalments. Interest runs on the unpaid balance for land and buildings (and shares in investment, dealing or land companies), but instalments on other qualifying shares and on business or agricultural property carry interest only if paid late.
How do I report gifts on IHT403?
List each gift with date, recipient, gross value, and any exemption used (£3,000/year AE, carry-forward of one year, £250/person small gifts, wedding gifts up to £5,000 parent / £2,500 grandparent / £1,000 other, regular gifts from surplus income). HMRC applies taper on the tax: 0% relief in years 0–3, then 20/40/60/80% in years 3–4/4–5/5–6/6–7 respectively, fully exempt at 7+ years.
Can I amend an IHT400 after submission?
Yes — file a corrective account using form C4. Additional IHT plus interest may become due, or HMRC may refund overpaid IHT.
What if the estate has no property but still needs IHT400?
Common — high-value investment portfolios, trust interests, or significant lifetime gifts can push an estate into full-reporting territory even without UK real estate. You still file IHT400 but skip IHT405. The Residence Nil-Rate Band doesn't apply without a qualifying dwelling.
How long does probate take after filing IHT400?
Timing depends on the estate and jurisdiction. In England and Wales, HMRC issues a unique probate reference code after processing the IHT400 information; the executors then use that code in the probate application. Northern Ireland uses IHT421. Check the current HMRC and probate guidance rather than relying on a fixed processing estimate.
HMRC documents checked October 2026. IHT400 structure and schedules follow current HMRC guidance. This walkthrough is general
information — complex estates (business relief, agricultural relief, foreign domicile) should use a specialist
solicitor or accountant.
