Probate · for executors paying UK Inheritance Tax
ProbateClock is an Inheritance Tax deadline tracker for executors dealing with an estate in the UK. You enter the date of death and your own estimate of the tax, and it shows the payment deadline, which is the end of the sixth month after the month of death, with an interest meter beside it. Once that date passes, the meter adds one day of interest at a time at the HMRC late payment rate shown on screen. A checklist works back from the deadline through the reference number, form IHT400, the Direct Payment Scheme and the probate application.
Enter the date of death and your estimate of the tax, and the meter appears at once. Before the deadline it stays at £0.00 and tells you what a single day would add after it. Once the date has passed, each new day adds one day of interest on your figure at the HMRC rate printed underneath, and the next step to take sits right below the number.
The checklist sets out the usual order: finding the money, getting an Inheritance Tax reference number at least three weeks before you pay, form IHT400, paying through the Direct Payment Scheme or a transfer, then applying for probate. Each step carries one line on why it sits where it does and the GOV.UK or HMRC page it comes from. Ticking a step leaves a quiet check mark and nothing more.
The calculation details show how the number was built: your figure, the HMRC late payment rate and the date it was last checked, the day interest started, and how many days have been counted. HMRC moves the rate when the Bank of England base rate changes, so you can enter a new rate yourself. Days already counted keep the rate they had.
Inheritance Tax on a death is due by the end of the sixth month after the month the person died. GOV.UK gives the example of a death in January, with the tax due by 31 July. It is easy to read that as six months from the date of death. Someone who died on 14 January has until 31 July, not 14 July, and a death on 31 August runs to the last day of February, which is the 29th in a leap year.
ProbateClock works from that month-end rule as soon as you enter the date of death. Interest begins the day after the deadline, so before then the meter shows none. It will not pretend the estate has been building up interest since the day of the death, because it has not.
For a lot of families the deadline ends up in someone's head, on the back of a solicitor's letter, or in a spreadsheet started on a hard evening. HMRC's own Inheritance Tax interest calculator gives a figure for one payment date, which is useful, but it does not stay with you between visits, and it does not mention that the reference number needs three weeks of lead time.
The pieces also arrive out of order. The money to pay the tax is often in the deceased's own accounts, yet GOV.UK notes that you usually have to pay some of the tax before probate is granted. The way through, the Direct Payment Scheme, lets banks pay HMRC straight from those accounts, but it sits on a different page from the deadline, and the reference number it needs is on another.
Open the app and the home screen answers two questions: how far you are from the deadline, and what comes next. Before the date, that is a count of days and the cost of one day after it. After the date, it is the interest added so far and the amount added today. Beneath either sits one card naming the next unticked step, so a number is never shown without something you can do about it.
Reminders for each step and for the deadline are local notifications, and they are switched on only if you ask. The text on the lock screen stays neutral, along the lines of a step to check today, with no mention of a death, an estate, money or interest. Anyone glancing at your phone at work sees nothing personal.
Everything you entered can be changed later: the date of death, your estimate, the rate, the ticks and the payment date. Each change recalculates the deadline, the meter and the reminders together. When you mark the tax as paid, the meter stops on that date and shows the estimated interest up to it, without any fanfare.
HMRC's late payment interest rate is the Bank of England base rate plus 4 percentage points, a formula in force since 6 April 2025. When we checked on 1 October 2026 it was 7.75%, the rate in force since 9 January 2026. It moved four times between April 2025 and January 2026, so treat any figure here, that one included, as a snapshot.
ProbateClock stores the rate with the date it was last checked and a note of the HMRC page it came from. It never fetches the rate itself, because the app makes no network requests at all. You can open the GOV.UK page in your browser and enter a new rate in settings, and if the stored rate has not been checked for 90 days the app says so, plainly.
ProbateClock does not work out how much Inheritance Tax the estate owes. It does not value property, apply the nil-rate band, suggest ways to reduce the bill, fill in IHT400 for you, or point you to a solicitor. The figure on the meter is interest on the amount you entered, nothing more, and there is no field anywhere for contact details.
It also has no memorial pages, journal or photos. Those belong somewhere gentler. This is the practical side of the six months, kept calm: no red warnings, no countdown theatrics, no celebration when a step is done.
The tax deadline and the interest rules apply across the UK. The checklist ends with applying for probate in England and Wales. In Scotland the court step is confirmation from the sheriff court, and Northern Ireland has its own probate rules; ProbateClock does not walk you through either.
ProbateClock organises public guidance from GOV.UK and HMRC and makes an estimate from figures you enter. It is not tax or legal advice. The interest HMRC actually charges is the figure that counts, and for a complicated estate it is common to speak to a solicitor or tax adviser.
By the end of the sixth month after the month of death, so a death in January means the tax is due by 31 July. ProbateClock shows that date as soon as you enter the date of death, and HMRC charges interest on anything still unpaid after it.
No. You enter your own estimate, for example from HMRC's guidance or from whoever is helping with the estate, and the app works out interest on that figure only. You can leave the amount blank and still use the deadline and the checklist; the meter lights up once you add it.
As simple interest on your figure, counted day by day from the day after the deadline at the HMRC late payment rate shown on screen, following the method in HMRC's IHT400 interest helpsheet. The calculation details list the rate, the date it was checked, the number of days and the sum, so you can compare it with HMRC's own interest calculator.
Nothing changes on its own, because ProbateClock never goes online. You enter the new rate in settings and it applies from then on, while days already counted keep their old rate. If the stored rate has not been checked for 90 days, the app points it out.
No. There is no account, no server and no analytics, and the app makes no network requests. The date of death, your estimate and your progress stay on your phone, and Delete all data in settings removes them along with any scheduled reminders.
The deadline and the interest work the same way across the UK, so the meter applies. The checklist's final step is written for probate in England and Wales; confirmation in Scotland and probate in Northern Ireland follow different court processes that the app does not cover.
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