Accounting and tax references and codes

Shortly after incorporating a company you’ll likely register for various taxes, have to activate online services, whilst your accountant attempts to gain agent authorisation for those taxes.  This all means you can be inundated with what seems like hundreds of codes, references and passwords.  Some are vital and will stay the same forever.  Others are one use then throwaway codes.

We’ve summarised all the main ones here with an explanation of what they are and if/why they’re important to you.  Immediately below is a downloadable/printable form you can use and complete with details for your own business.  Some are sensitive information, so of course only complete what you’re happy to and save somewhere secure:

Accounting/tax references/codes
Accounting/tax references/codes

Companies House related

Companies House registration number – 8 digits, all numbers.  Publicly available, permanent, and is unique to your Limited Company.

Authentication code – 6 digits, random combination of letters/numbers.  Password to file things online with Companies House


HMRC related

Company UTR – 10 digits, all numbers, used for corporation tax purposes.  HMRC don’t make it easy by often putting it as part of a longer reference.  Eg the first time you’ll get it, it’ll be the bold part of a reference in the format “123 12345 67890 A”.  It’ll also form part of a payslip reference, format “1234567890A00101A”.

Personal UTR – 10 digits, all numbers, used for personal tax (ie self assessment) purposes.

VAT registration number – 9 numbers, often spread out slightly in the format “123 4567 89”.  Sometimes preceded with “GB” if being used in an international setting.

Employer’s PAYE reference – 3 numbers, “/”, 2 letters, then further numbers (quantity varies), so something like “123/AB12345”.  Unique payroll reference for your business.

Accounts Office Reference Number – 3 numbers, 2 letters, 8 numbers, eg “123AB00012345”.  Another unique payroll reference for your business.  This one is normally used when making payments.

Gateway ID – 12 digits, used for logging in to the HMRC portal.

You will also on occasion get the below one use codes (not on the form above as by their nature no point in keeping a permanent record):

Activation code – following attempting to enrol for an online HMRC service (within your HMRC portal login), HMRC will send out an activation code by post.  This is a one use code to enter on your HMRC portal login to confirm enrolment of that online service.  This is a security measure by HMRC, as it means only those with access to post at the address HMRC have linked to that tax will be able to enrol the online service.

Authorisation code – following your accounting finding out some of the tax references listed above, they’ll likely request agent authorisation.  Data protection means HMRC won’t divulge your or your company’s financial details to anyone, so an account needs to be appointed as your authorised agent before HMRC will discuss your affairs with them.  HMRC will send a letter out to you with code to forward to your accountant if you agree with them being your agent, starting:
“CT…” for corporation tax,
“SA…” for self assessment,
“VT…” for VAT,
“PE…” for PAYE.

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