Which version of IHT400 does this guide cover?
This guide is checked against HMRC's 19-page IHT400 marked HMRC 04/26. Always open the current GOV.UK publication page before filing because HMRC can replace forms and notes.
IHT400 Field by Field: What Every Box Means | ProbateHelp
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.
Also searched as: i h t400 field by field.
Frequently asked questions
Can I submit IHT400 online?
Use the current GOV.UK IHT400 publication and submission instructions. The April 2026 form can be completed on screen but must be printed, signed and sent with the required schedules and evidence. Do not rely on a saved old PDF or an old postal address.
Does no tax due mean IHT400 is unnecessary?
No. Full details can still be required even where no tax is due, for example because of the estate value, gifts, trusts, foreign assets or other HMRC conditions. Use the current GOV.UK estate checker rather than a single threshold test.
When must IHT400 be sent?
The April 2026 form says it must be sent within 12 months of the date of death. Interest can be payable after six months, so tax may need attention before the filing deadline. Check the current form notes for the estate's dates.
Can an executor complete IHT400 without a professional?
An executor can complete it, and HMRC can perform the tax calculation in some cases. Professional tax or legal help may be sensible where values, gifts, trusts, foreign assets, business or agricultural relief, residence status, reduced-rate charity tax or ownership are uncertain.
What if a figure later changes?
The declaration requires reasonably practicable enquiries and identifies provisional figures. Tell HMRC when a material figure changes and pay any additional tax and interest due. Penalties depend on the facts and behaviour, so do not assume every mistake is treated the same way.