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Where to find your company UTR for Corporation Tax

Last updated: 12 October 2026

Short version. Corporation Tax UTR is the 10-digit Unique Taxpayer Reference HMRC gave your company for Corporation Tax. It is not a personal UTR or the Companies House company number. Find it on HMRC letters about Corporation Tax or a previous Company Tax Return. If you cannot find it, request it online and HMRC will send it to the company's registered business address. You enter it once, in the final filing dialog, and it is used for every CT600 in that filing.

Go to the steps and entry details

On this page

10 digitsHMRC onlyWhere you see it: Filing credentials › HMRC Government Gateway › Corporation Tax UTR

What this guide covers

Corporation Tax UTR is the 10-digit Unique Taxpayer Reference HMRC gave your company for Corporation Tax. It is not a personal UTR or the Companies House company number.

  • The field accepts digits only and stops at 10. Anything else you paste, such as spaces or letters, is dropped.
  • It may already be filled in from your company details. You can change it in the dialog before you submit.
  • HMRC checks the UTR against your Government Gateway account. A wrong UTR is refused with the same Authentication Failure as wrong sign-in details. If HMRC refuses your details
  • Companies House does not use it. A Companies House only filing does not ask for it.

Is this the right guide for you?

Use it if all of these are true

  • You are sending a CT600 to HMRC and need the company's UTR.
  • You are not sure which HMRC number is the right one, or you cannot find it.

Do not use it if

What a company UTR is

A Corporation Tax UTR is a 10-digit HMRC reference. GOV.UK says it might just be called a ‘tax reference’. HMRC gives a company one when it sets up the company's Corporation Tax record. A club or other organisation that files a CT600 has its own UTR in the same way.

Where to find it

Look first in these places:

  • letters from HMRC about Corporation Tax, such as a notice to file a Company Tax Return or a payment reminder
  • a previous Company Tax Return
  • the company's business tax account, if Corporation Tax is already added there

HMRC's Find your UTR number page confirms where to look and how to request a replacement.

If you cannot find it

Do not guess and do not use another company's number. A limited company can request its Corporation Tax UTR online, and HMRC sends it to the business address registered with Companies House, so check that address is current first. GOV.UK: if you have a limited company

HMRC's Corporation Tax general enquiries page says you can ask for a copy of your Corporation Tax UTR if you do not know it, but its advisers cannot give you the reference over the phone.

UTR, company number and personal UTR

These are different references:

  • Company UTR: the company's 10-digit Corporation Tax reference, issued by HMRC.
  • Company number: the number Companies House issues when the company is incorporated.
  • Personal UTR: your individual Self Assessment reference, if you have one.

Only the first one belongs in Corporation Tax UTR. A company number or personal UTR leads HMRC to reject the filing.

Common mistake: the wrong number

The field only checks the length. A short number stops you before you submit, but a 10-digit number that is not the company's UTR reaches HMRC and is refused.

  • A company number or part of a UTR. The Submit button stays grey and the dialog shows UTR must be 10 digits, with how many digits you entered.
  • Your personal Self Assessment UTR. It is also 10 digits, so the dialog accepts it. HMRC then refuses the CT600 with an Authentication Failure.
  • Another company's UTR. If you run several companies, check the letter is addressed to the company you are filing for.

Worked example

Company
Chestnut Example Ltd
Accounts period
1 July 2025 to 30 September 2026 (15 months, so two CT600s)
Where the director found the UTR
On HMRC’s notice to deliver a Company Tax Return, addressed to Chestnut Example Ltd
What the director entered
The 10 digits from that letter, once, in Corporation Tax UTR
What happened
Both CT600s were sent to HMRC with that UTR

The company and all figures on this page are fictional.

When you need it

You need the company UTR to add Corporation Tax to a Government Gateway account and to file a CT600. You do not need it for a Companies House accounts-only filing. For the HMRC side, the Government Gateway account also needs Corporation Tax added and activated for the same company.

See how to set up Government Gateway for Corporation Tax if the company's UTR is not yet linked to an HMRC online account.

Where you enter it

  1. Review & file

    Continue
    Click Continue to submission

  2. Filing credentials

    Filing targets
    HMRC tickedThe UTR field shows only when HMRC is ticked.
    Corporation Tax UTR
    The 10 digits from your HMRC letterIf a number is already there, check it against the letter and correct it if needed.
    Gateway User ID
    The user ID of the account that lists this UTR
    Gateway Password
    The password for that same user ID

    Complete the director and declaration, then click Submit to HMRC. If the button stays grey, the line above it starting Still needed before you can submit: names what is missing.

    More help: Gateway User ID and Gateway Password

  3. After you submit

    The UTR you entered is saved with this filing, so it is filled in again if you need to resubmit. If HMRC refuses it, the filing page reads Gateway details and UTR not accepted.

    More help: Fix an Authentication Failure

Two CT600s for a long period

When your accounts period ends more than 12 months after it starts, even by one day, HMRC needs two CT600s. Both returns are for the same company, so they use the same UTR. You enter it once and we send both CT600s with it. If HMRC refuses the UTR, it usually refuses both returns, because both were sent with it. How the dates are split

More help: Sending two CT600s again

Sample outcome

One UTREntered once for Chestnut Example Ltd and used for both CT600s.
10 digitsA shorter number cannot be submitted. The dialog says how many digits you entered.
HMRC onlyCompanies House filings do not use the UTR.Authentication code

Not the right guide?

Open the guide for the detail you need.

Setting up a Government Gateway accountAdd Corporation Tax with your UTR and activate it.HMRC rejected my sign-in detailsAuthentication Failure after you submitted.Companies House authentication codeThe 6-character code for filing accounts.

Looking for a different field or step? See all filing wizard guides →

Official sources

Whether this route matches your filings is for you to decide, yourself or with your accountant.

Example companies and figures are fictional. Field names match the filing wizard as of 12 October 2026.