# Probate timeline calculator: the inheritance tax deadline, the IHT400 window, when to apply for the grant, and the dates that follow it > Enter the date of death and the tax route to get the inheritance tax date, the IHT400 deadline, the earliest probate application, the fee and post-grant dates. - Page to cite: https://aeolookup.com/solicitors/probate-timeline-calculator-key-dates/ - Publisher: AEO Lookup (https://aeolookup.com/) - Section: Solicitors, Probate and private client - Published 1 October 2026 - Key fact: For a death on 15 March 2026 with an IHT400 to file, inheritance tax is due by 30 September 2026 and the account by 31 March 2027; if the IHT400 goes to HMRC on 1 June 2026 the earliest probate application is 29 June after HMRC's 20 working days; the fee is £526 on an estate over £5,000; and from the grant, Inheritance Act claims run for six months, while the deed of variation deadline is 15 March 2028. - Sources: GOV.UK "Pay your Inheritance Tax bill: deadline" (end of the sixth month after death; interest after) and "Applying for probate" (usually within 12 weeks), read 2026-10-01; HMRC guidance to wait 20 working days after sending the IHT400; probate fee £526 for estates over £5,000 and £2 for each extra copy ordered with the application (GOV.UK "Applying for probate: fees", read 2026-10-01); Inheritance (Provision for Family and Dependants) Act 1975 s4; IHTA 1984 s142 (two years). Tested in headless Edge 2026-10-01. "Probate process UK" and "how to start probate process" are typed by executors; "probate timeline" is typed by the fee earner who has to tell them. The honest answer is that some dates are fixed by law, one is an estimate, and the two are usually muddled together. This calculator separates them. **Free tool on the page:** Probate timeline calculator: the inheritance tax deadline, the IHT400 window, when to apply, and the dates after the grant. It runs in the browser at https://aeolookup.com/solicitors/probate-timeline-calculator-key-dates/#tool and asks for no sign-up. ## The dates fixed by law **Inheritance tax payment: the end of the sixth month after the month of death.** A death on 15 March means 30 September. HMRC charges interest from the next day whether or not the grant has issued, which is why executors pay on account before the figures are final. Tax on land, and on some business and unquoted shares, can be paid in ten yearly instalments, the first by this date. **The IHT400 account: twelve months from the end of the month of death.** 31 March of the following year for the March death. Late accounts attract penalties separate from the interest. **The earliest probate application: 20 working days after the IHT400 is sent.** HMRC asks applicants to wait so that its IHT421 reaches the probate registry; an application sent sooner is stopped. The calculator counts Monday to Friday and does not remove bank holidays, so add any that fall in the period. **The probate fee: £526 for an estate over £5,000**, nothing below, plus £2 for each extra copy of the grant ordered with the application. Copies ordered later are £16 each, so count the banks, registrars and pension providers first. **After the grant: six months for Inheritance Act claims.** A claim under the Inheritance (Provision for Family and Dependants) Act 1975 must be issued within six months of the grant, and many executors do not distribute before that date for that reason. **Two years from death for a deed of variation** to be read back for inheritance tax and capital gains tax. **The executor's year**: twelve months from death, before which beneficiaries cannot ordinarily insist on distribution and after which interest on pecuniary legacies runs. ## The date that is an estimate How long the registry takes. GOV.UK says the grant usually arrives within twelve weeks of the application and can take longer if information is needed. That sentence is the whole of the official timescale; a firm that gives an executor a firmer date is giving its own guess. The calculator prints the official wording and nothing more. ## Excepted estates Where no IHT400 is needed (an estate below the threshold, or an exempt estate passing to a spouse, civil partner or charity, with the limits as at the date of death), there is no tax date and no 20-day wait; the application can go in once the estate information is complete. The calculator drops the tax rows and keeps the rest. ## What is not calculated A section 27 Trustee Act 1925 notice closes claims two months after publication; the date depends on when the notice runs, so the calculator notes it without a date. Income tax to the date of death and the estate's own tax returns have their own deadlines through HMRC. And the dates assume England and Wales; Scotland's confirmation process differs. ## In the firm An AI Probate Clerk set up by Overlyft ![](https://aeolookup.com/img/d/ours-badge.png) produces this list on the day a probate file opens and diaries each date in the case management system, then chases the estate information against the IHT400 deadline and the tax against the payment date. The supervising solicitor checks every date against the file before any of them is given to an executor; where the estate has a trust, a business or a foreign element, the list is a starting point for the solicitor, not an answer. The [file-opening checklist](https://aeolookup.com/solicitors/client-care-letter-checklist-new-matter/) covers the client care letter for an uncontested probate, which is on the [SRA transparency list](https://aeolookup.com/solicitors/sra-transparency-rules-price-information-what-to-publish/). This is general information, not legal or tax advice. ## Short answers from this page **When is inheritance tax due after a death?** By the end of the sixth month after the month of death; interest runs from then. The IHT400 account is due within 12 months of the end of the month of death. For a death on 15 March 2026, tax is due by 30 September 2026 and the account by 31 March 2027. **How soon after sending the IHT400 can I apply for probate?** After 20 working days, the time HMRC asks applicants to allow before the probate application is made. An IHT400 sent on 1 June 2026 means the earliest application is 29 June. The probate application fee is £526 where the estate is over £5,000. **What are the key dates in a probate matter?** Inheritance tax by the end of the sixth month after death; the IHT400 within 12 months; 20 working days after the IHT400 before applying for the grant; six months from the grant for an Inheritance Act claim; and the executor's year, twelve months from death, after which interest can run on unpaid legacies. A deed of variation must be made within two years of death. --- ![](https://aeolookup.com/img/d/owner-line.png) Overlyft: https://overlyft.com/ General information for UK small firms, not legal, tax or financial advice.