Limited company numbers explained: what each one is
Your limited company has a lot of numbers. These limited company numbers are the ones you keep being asked for: what each one is, where to find it, and when it comes up.
Every entry has the same three beats: this is that, where to find it, and when it comes up. Where there is a longer guide or a free tool, it is linked underneath.
The name-tag table
| Number | What it is, in one line | Who gives it |
|---|---|---|
| Company number | The 8-character ID of your company at Companies House | Companies House |
| Authentication code | The six-character code that signs your online filings | Companies House |
| Personal code | The 11-character code for one person who verified their identity | Companies House |
| Registered office | Your official address for legal post | You provide it |
| SIC code | A code for what your company does | You pick it from a list |
| Confirmation statement | The yearly check that your Companies House record is right | You file it |
| Accounting reference date | The date your financial year ends | Set from your incorporation date |
| UTR | Your company's Corporation Tax number | HMRC |
| Corporation Tax reference | Probably the UTR under another name | HMRC |
| CT600 | The Company Tax Return form | HMRC |
| VAT number | Nine digits, often with GB in front | HMRC |
| PAYE employer reference | The slash number on your P60, like 123/AB456 | HMRC |
| Accounts Office reference | A 13-character PAYE payment reference | HMRC |
| EORI number | A customs number that starts with GB | HMRC |
The Companies House numbers
Company number
This is that: the 8-character number that identifies your company at Companies House.
Where to find it: your company's page on the Find and update company information service, labelled "Company number". You can search by company name or number.
When it comes up: forms, banks and suppliers keep asking for it.
Authentication code
This is that: a six-character code, letters and numbers, that works like your company's signature for online filings.
Where to find it: Companies House posts it to your registered office after you request it in WebFiling.
When it comes up: whenever you file for your company online.
More: Companies House authentication code
Personal code
This is that: an 11-character code for one person, not for the company, given once they have verified their identity with Companies House.
Where to find it: if you verified with GOV.UK One Login, sign in to Companies House.
Then open Manage account to see your code.
When it comes up: directors and people with significant control use it. It is not the company authentication code.
More: Companies House authentication code
Registered office
This is that: your company's official address for statutory mail and legal documents, a physical location in the country the company is registered in.
Where to find it: on your company's page, labelled "Registered office address".
When it comes up: it is where official post and legal documents are sent.
SIC code
This is that: a code that describes what your company does.
Where to find it: choose it from the condensed list on GOV.UK, using the trade description lookup linked there.
When it comes up: when you file with Companies House, which accepts only codes on that list.
Confirmation statement
This is that: the yearly check that the information Companies House holds about your company is up to date.
Where to find it: your confirmation date and filing deadline are on the company information register.
When it comes up: you must file at least one every 12 months, and you can file up to 14 days after the review period ends.
More: the free deadlines tool.
Accounting reference date
This is that: the date your financial year ends, also called your year end.
Where to find it: your first year end is the end of the month you were incorporated in, a year later. After that, your company's page shows when your next accounts are made up to.
When it comes up: a private company's accounts are normally due 9 months after it.
More: the free deadlines tool.
The HMRC numbers
UTR
This is that: your company's Unique Taxpayer Reference for Corporation Tax, usually a 10-digit number.
Where to find it: on tax returns and other HMRC letters about Corporation Tax. If you have lost it, you can request it online.
When it comes up: whenever you deal with HMRC about Corporation Tax.
More: company UTR number
Corporation Tax reference
This is that: not an official name. HMRC says your Corporation Tax UTR might be labelled "reference", "UTR" or "official use" on its forms, so a form asking for a Corporation Tax reference usually wants the UTR. If you are not sure, ask whoever sent the form. Paying a bill is different: that uses a 17-character payment reference that changes with each accounting period.
Where to find it: the same places as the UTR, on tax returns and HMRC letters about Corporation Tax.
When it comes up: when a Corporation Tax form asks for a "reference".
More: company UTR number
CT600
This is that: the Company Tax Return form for Corporation Tax.
Where to find it: GOV.UK has a guide to completing it.
When it comes up: it is due 12 months after the end of the accounting period it covers.
More: Corporation Tax due date and the free Corporation Tax deadline tool.
VAT number
This is that: 9 numbers, sometimes with GB at the start.
Where to find it: on your VAT registration certificate.
When it comes up: it appears on invoices and receipts.
More: VAT number format UK and the free VAT number checker.
PAYE employer reference
This is that: 3 numbers, a forward slash, then up to 10 letters or numbers, like 123/AB456.
Where to find it: on your P60 and on letters from HMRC about PAYE.
When it comes up: when a form asks for your "PAYE reference" or "Employer PAYE reference".
More: PAYE reference number vs Accounts Office reference
Accounts Office reference
This is that: a 13-character reference, like 123PX00123456.
Where to find it: on HMRC letters about PAYE, including those from when you registered as an employer.
When it comes up: when you pay PAYE early or late, you add 4 extra numbers to it.
More: PAYE reference number vs Accounts Office reference
EORI number
This is that: a customs number. For Great Britain it starts with GB.
Where to find it: you apply for it on GOV.UK, and you get it immediately unless HMRC needs to make checks.
When it comes up: you may need one if you move goods between Great Britain and another country.
How Kofolio keeps them on one card
Each company in Kofolio is a card, and you add it by typing its 8-character company number. Companies House fills in the name, status, registered office, incorporation date, year end and directors.
You type the rest. The card has fields for the company number, authentication code, Corporation Tax UTR, VAT number, PAYE employer reference, Accounts Office reference, EORI, addresses, directors and bank accounts, and you can add a custom field of your own.
There is no separate field for a SIC code or a personal code. If you want them on the card, add each as a custom field.
Click a value to copy it. The authentication code and UTR are hidden until you press show, and they still copy while hidden. Press V for the VAT number, U for the UTR and C for the company number.
Cmd+K searches every value across every company.
The card counts your accounts, confirmation statement, Corporation Tax and VAT dates down in days.
Kofolio stores and copies. It files nothing for you, and it is an organiser, not an adviser.
Frequently asked questions
Which numbers come from Companies House?
The company number, the company authentication code and a person's personal code.
Which numbers come from HMRC?
The Corporation Tax UTR, the VAT number, the employer PAYE reference, the Accounts Office reference and the EORI number.
Is the Corporation Tax reference the same as the UTR?
Probably. HMRC says the UTR might be called "reference", "UTR" or "official use", but no GOV.UK page says the two names are the same in those words.
Are the PAYE reference and the Accounts Office reference the same?
No. The PAYE reference looks like 123/AB456, and the Accounts Office reference has 13 characters.
All your numbers, one click away
Add your company to Kofolio and keep every number on one card. Kofolio is free. Find your company