IHT422: Getting an Inheritance Tax Reference Before You Pay

This guide follows GOV.UK's IHT422 page, updated in June 2026, the Pay your Inheritance Tax bill guide and the IHT400 Notes, as of October 2026.

When you need a reference, and when you don't

The IHT400 Notes are clear on box 3 of the IHT400: if there's Inheritance Tax to pay, you need a reference number before you send the form. If there's no tax to pay, you don't need to apply or fill in box 3.

That makes the reference a tax-due step, not a paperwork step for every estate.

The 3 week rule, and why it matters

GOV.UK says to get the reference at least 3 weeks before you make a payment, and the IHT400 Notes say at least 3 weeks before you plan to send the IHT400. The pressure comes from the deadline: Inheritance Tax is due by the end of the sixth month after the death. HMRC's own example is a death in January, with tax due by 31 July.

Interest starts if you miss that date. Since you usually need to pay something before you can get probate, a late reference can hold up the whole estate.

How to apply

1. Go to the IHT422 page on GOV.UK and start the online form.
2. Sign in with your sign in details, which you can create if you don't have them, or use an email address.
3. Wait for HMRC's letter with the reference number, and keep it with the estate papers.

The IHT400 Notes (2022) still describe filling in Schedule IHT422 and posting it. GOV.UK's current IHT422 page describes the online form, so start there.

Trusts use a different form

The reference for a trust payment comes from form IHT122, posted to HMRC, not from IHT422. That's the route for exit charges, 10 year anniversary charges and other trust events reported on the IHT100 forms. HMRC's IHT100 notes say to leave the reference box blank if you don't have one yet.

What the reference is used for

The number ties every payment to the right estate. GOV.UK says to use it as the payment reference for bank transfers, and to write it with the name of the person who died on the back of any cheque, which goes to the Inheritance Tax Team separately from other forms. It also goes on the IHT400 itself.

Getting it wrong has a cost. HMRC warns that a wrong reference can delay a payment or put it against a different tax bill you owe. If that happens, you contact Inheritance Tax general enquiries to have it moved.

Ways to pay once you have it

• Approve a payment through your online or mobile bank, which is usually instant but can take up to 2 hours to show.
• Bank transfer by Faster Payments, which usually arrives the same or next day, CHAPS, usually the same working day, or Bacs, usually 3 working days.
• At your bank or building society, by cash or cheque.
• By cheque through the post.
• From the deceased's own accounts through the Direct Payment Scheme, using form IHT423.
• Using British government stock.

You can pay from your own account, or a joint account with the person who died, and claim it back from the estate once you have probate. HMRC doesn't send a receipt for each payment, and writes when everything is paid.

Payments on account

If you don't know the final figure yet, GOV.UK says you can pay before you know the exact amount. These are called payments on account, and you still need the reference first.

Northern Ireland and Scotland

If you're using the Direct Payment Scheme in Northern Ireland, you include the IHT421 probate summary with the IHT400. In Scotland it's Confirmation form C1. HMRC stamps and returns that form, and the stamped copy is confirmation that you've got probate. In England and Wales, HMRC sends a code so you can apply for probate online.

Paying from the deceased's accounts

The Direct Payment Scheme lets banks, building societies and investment providers such as NS&I pay some or all of the tax from the deceased's accounts, and you can start it before probate. Ask each provider to make you a personal representative, get your reference, then fill in a separate IHT423 for each account and send it to that provider. The IHT400 and supporting papers go to HMRC's Inheritance Tax Team at BX9 1HT.

If you can't pay

If you can't release funds from the estate and can't pay another way, GOV.UK says you can ask to postpone paying Inheritance Tax. Interest still applies after the due date, so that's a request to make early, not a way round the deadline.

Our late filing penalty appeal explainer covers a different form for readers who prefer to file it themselves.

The verdict

If the estate owes Inheritance Tax, apply for the IHT422 reference as soon as you know, not when the IHT400 is finished. Three weeks is the minimum lead time, and the six-month payment deadline doesn't move. Use the number exactly as HMRC sends it on every payment.

Readers often ask about this next, and our overseas estate inheritance tax form explainer answers.

Frequently asked questions

Can I pay Inheritance Tax before I know the exact amount?

Yes. GOV.UK calls these payments on account, and you need the reference number first.

What if I use the wrong Inheritance Tax reference?

The payment may be delayed or used for a different tax bill. Contact Inheritance Tax general enquiries to have it moved.

What is IHT422?

HMRC's application for an Inheritance Tax reference number, which you need before you send the IHT400 and pay any tax.

How long does it take to get an Inheritance Tax reference?

HMRC says to apply at least 3 weeks before you plan to pay or to send the IHT400.

Do I need an IHT422 if there's no tax to pay?

No. The IHT400 Notes say you don't need to apply for a reference if there's no Inheritance Tax to pay.

Is IHT422 a paper form?

Not now. GOV.UK says you apply online using sign in details or an email address.

How do I get a reference to pay tax on a trust?

Use form IHT122 and post it to HMRC. IHT422 is for estates.