How to get an inheritance tax reference number

You get an inheritance tax reference number by applying to HMRC before you send the IHT400 or pay any tax. For a person's estate, the executor or administrator applies online through HMRC's service. For a trust event or a lifetime gift that is immediately chargeable, you apply on form IHT122 by post. HMRC asks you to apply at least three weeks before you plan to make a payment. The reference number links your forms and payments to the right estate at HMRC. Without it, HMRC cannot match a payment to the estate, and you cannot complete the IHT400. This guide explains when you need one, how to apply, and what to do if it is taking longer than expected.

When do you need an inheritance tax reference number?

You need a reference number if:

• you are sending a full inheritance tax account (form IHT400) for someone who has died, whether or not tax turns out to be payable
• inheritance tax is due on the estate and you need to pay it, including paying before probate is granted
• a trust has a chargeable event, such as a ten-year anniversary or assets leaving the trust, and you are reporting it on one of the IHT100 forms
• someone has made a lifetime gift on which tax is payable straight away, such as a large gift into a discretionary trust

You do not need one if the estate is an excepted estate. In that case you report the estate's values in the probate application and no inheritance tax form is sent. Our guide to excepted estates and the old IHT205 explains how to tell.

How to apply for a reference number for an estate

For someone who has died, apply using HMRC's online service, Inheritance Tax: application for an Inheritance Tax reference (IHT422). The IHT422 used to be a paper form, but it is now completed online. You can sign in with Government Gateway details or apply with just an email address. Have the following to hand before you start:

• the deceased's full name, date of birth and date of death
• their last permanent address
• their National Insurance number or Unique Taxpayer Reference, if you know it
• your own name and contact details as executor or administrator, or those of the solicitor acting for the estate

Apply as soon as you know an IHT400 will be needed. You will need the reference on the front page of the IHT400 and on every payment.

How to apply for a trust or a lifetime gift: form IHT122

If the reference is for a chargeable event rather than a death, such as a trust's ten-year anniversary charge, an exit charge, or a gift into trust, use form IHT122: Apply for an Inheritance Tax reference after a chargeable event. You fill it in and post it to HMRC. Trustees usually need a reference for each chargeable event they report. Our guide to IHT100 forms explains which form covers which event.

How long does it take?

HMRC asks you to get your reference at least three weeks before you make a payment. Posted IHT122 applications take longer than the online service, so allow extra time for trust and lifetime events. Timing matters because inheritance tax on an estate is normally due by the end of the sixth month after the month of death. Interest starts after that date, even if you are still waiting for your reference. Our guide to inheritance tax interest explains how it is charged.

What if your reference number has not arrived?

• Check your emails and post. HMRC sends the reference to the contact details given on the application, so check spam folders and the address of the person named as the contact.
• Do not apply twice. A second application can create a second record for the same estate and slow things down.
• Contact HMRC. If three weeks have passed, contact the Inheritance Tax payment enquiries team with the deceased's details and the date you applied.
• Keep a note of what you have done. If interest becomes due because of a delay, a record of when you applied will help.

Paying inheritance tax from the deceased's bank account

Many executors do not have the money to pay inheritance tax before probate is granted. HMRC's Direct Payment Scheme lets banks, building societies and some investment providers pay the tax directly from the deceased's accounts, before probate. To use it, you need your reference number first. You then:

1. ask each provider to register you as the personal representative
2. complete form IHT423 for each account you want HMRC to be paid from, and send it to that provider
3. send the IHT400 and its schedules to HMRC

Not every provider takes part in the scheme, so check with each one early. Our guide on when inheritance tax is paid in probate covers the other ways to pay, and Struggling to pay an inheritance tax bill? covers paying by instalments.

What happens next?

Once you have the reference, you can finish the IHT400 and its schedules, pay any tax due, and apply for probate. Our guide to what happens after you've completed your IHT400 form sets out the timeline from there.

Frequently asked questions

Is the inheritance tax reference number the same as the deceased's tax reference?

No. The inheritance tax reference is a separate number that HMRC issues for the estate or chargeable event. It is not the deceased's National Insurance number or their Self Assessment Unique Taxpayer Reference.

Do I need a reference number if no inheritance tax is due?

If the estate is an excepted estate, no. If you have to send an IHT400, yes, even if the reliefs and allowances mean no tax is payable in the end.

Can a solicitor apply for the reference for me?

Yes. A solicitor acting for the estate can apply and can be named as HMRC's contact, so correspondence goes to them.

Is there a fee?

No. HMRC does not charge to issue an inheritance tax reference number.

How Roche Legal can help

We deal with HMRC on behalf of executors and trustees every week, from getting the reference number to completing the IHT400 and arranging payment through the Direct Payment Scheme. If you would like us to take this on, or to check the forms before you send them, contact the Roche Legal team or book a discovery call.

Further reading

• What happens after you've completed your IHT400 form?
• Inheritance tax thresholds, rules and allowances for 2026
• IHT100 forms: when you need one and how to complete it
• Inheritance tax calculator

This guide is general information, not legal or tax advice. Rules can change, so please speak to us about your situation.

Sources used

• GOV.UK, Pay your Inheritance Tax bill: get a reference number
• GOV.UK, Inheritance Tax: application for an Inheritance Tax reference (IHT422), updated 5 June 2026
• GOV.UK, Apply for an Inheritance Tax reference after a chargeable event (IHT122)
• GOV.UK, Pay from the deceased's bank, savings or investment account (Direct Payment Scheme, IHT423)