A plain-English walkthrough of every page and question in the IHT400 form — what HMRC is asking, what figures to enter, which schedules you need, and the answers that cause delays.
This guide is part of ProbateHelp's Inheritance Tax guide cluster. Estimated reading time: 30 min.
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No. As of April 2026, the IHT400 must be printed and posted to HMRC's Inheritance Tax office in Nottingham. HMRC has announced plans for a digital route but it is not yet available. You can download the form and fill it in on-screen before printing.
The IHT205 (now replaced by the online excepted estates return for deaths after 1 January 2022) was a shorter form for smaller estates that do not owe tax. The IHT400 is the full inheritance tax account required when IHT is due, the estate exceeds £3 million, or the estate does not qualify as an excepted estate.
HMRC guidance says to allow 20 working days before starting your probate application where an IHT400 has been submitted. In practice, processing times can run longer during busy periods or where HMRC has questions. For England and Wales, you normally wait for HMRC's unique probate code rather than separate executor-handled IHT421 paperwork.
No. Many executors complete the IHT400 themselves, particularly for straightforward estates. The form is detailed but not legally complex. Where the estate includes business property, agricultural land, trusts, or significant foreign assets, professional help is worth the cost.
You can correct errors by writing to HMRC's Inheritance Tax office. If the correction increases the tax due, interest runs from the original payment date. If it reduces the tax, HMRC will refund the overpayment. Honest mistakes are not penalised, but deliberate undervaluation can attract penalties of up to 100% of the unpaid tax.
The IHT400 must be submitted within 12 months of the end of the month in which the person died. Tax is due within 6 months of the end of the month of death — so you will often need to pay before you have completed the full form. HMRC allows payment on account to avoid interest accruing.