Quick answers
- How long does a new Companies House authentication code take to arrive?
GOV.UK says it can take up to 10 working days. It is posted only, so request it well before any filing deadline. - Can Companies House email my authentication code or give it to me over the phone?
No. Companies House cannot email the code or tell it to you over the phone. - My authentication code was sent to our old address. What now?
If you cannot get post at the registered office, use Companies House’s service to send the code to an active officer’s home address, if the company qualifies. - Who can use the home address route?
It posts the code to an active officer’s home address that Companies House already holds.
In more detail
The code is a 6-character mix of letters and numbers that Companies House gives each company. You need it to file most changes online.
Companies House only sends it by post, and a new one can take up to 10 working days.
This guide shows where to look first, how to request a replacement, and what to do if you cannot get post at the registered office.
If you would rather not do it yourself, we can request a company authentication code for you.
What is a company authentication code?
A company authentication code is a six-character code of letters and numbers that Companies House issues to each company. It authorises information filed online, and GOV.UK calls it the equivalent of a company officer’s signature. The code belongs to the company, not a person, and it is different from a Companies House personal code.
You use the same code to file through Companies House WebFiling, Find and update company information, and commercial filing software. Companies House uses it to check that whoever files online is authorised to act for the company.
In practice, that means filings such as a confirmation statement, a change of registered office, or appointing or removing a director. Without the code, these filings cannot go through online.
A personal code is issued to an individual when they complete Companies House identity verification. Many filings now need both: the company’s code and the director’s personal code. A new company code does not replace a personal code.
Source: Company authentication codes for online filing (GOV.UK)
Where to find your company authentication code before requesting a new one
Companies House posts the code to the company’s registered office. A replacement takes time, so it is worth a quick search first, especially if a deadline is close.
| Where to look | Why it might be there |
|---|---|
| Post at the registered office | Companies House sends codes there. Check letters opened by a landlord, colleague or reception. |
| Your accountant or company secretary | Anyone who files online for the company may already hold the code. |
| Your formation agent or registered office provider | If they formed the company or handle its post, they may have received or forwarded the letter. |
| Your own records or password manager | A director can change the code to something more memorable in WebFiling, so it may be saved somewhere. |
| Paperwork from when the company was formed | If you kept the original company letters, the code may be among them. |
Authentication code sent to an old address
Companies House posts the code to the registered office shown on the public register. If the company has moved but the register was never updated, the letter goes to the old address. A fresh request will go there too.
First, check the registered office on the register using Find and update company information. If it is out of date, you cannot simply ask for the code to go somewhere new. You have two options, set out in the next section.
Remember that a change of registered office must be reported to Companies House within 14 days of the change taking place.
Source: Change a company’s registered office address (AD01) (GOV.UK)
Lost Companies House authentication code: how to request a new one
There are two official routes. Which one fits depends on whether someone can collect post at the registered office.
| Route | Where the code is posted | Key points |
|---|---|---|
| Standard request through Companies House WebFiling | The registered office on the register | Create an account or sign in, then follow the steps. Allow up to 10 working days. |
| Home address request through Companies House | An active officer’s home address, as Companies House already holds it | For when you cannot access the registered office. You need separate sign-in details for this service, not your WebFiling ones. Conditions apply (see below). Around 10 working days. |
Source: Company authentication codes for online filing (GOV.UK)
What if you cannot get post at the registered office?
If you cannot get post at the registered office, GOV.UK says Companies House can send the company authentication code to a home address instead. Its home address service posts the code to an active officer’s home address that Companies House already holds. Allow up to 10 working days for it to arrive, as with a standard request.
There are conditions. The service cannot be used if the company has filed a document online in the last 30 days, is not based in the UK, is not a limited company or LLP, or is dissolved. You need the company number and separate sign-in details for this service, which are different from WebFiling sign-in details. You also cannot view or change the officer’s home address during the request. So check first that Companies House has that officer’s latest home address.
Once the code arrives, you can change your registered office address online. The new address must be a physical address in the UK, in the same country the company is registered in. For example, a company registered in Scotland needs a registered office in Scotland. Someone acting for the company must be made aware of post delivered there, and senders must be able to get confirmation of delivery. A Royal Mail PO Box, or a similar service, is not allowed.
What about paper forms? GOV.UK now directs companies to change the registered office online. It lists the paper AD01 form only for companies that have been defaulted to the Companies House address, are in liquidation, are applying to be restored, or are unregistered companies. If none of these applies, use the home address route to get the code, then file the change online. If your company cannot use either route, contact Companies House before choosing another approach.
Source: Send a company authentication code to an officer’s home address (Companies House)
Companies House authentication code not working?
If your Companies House authentication code is not working, the usual causes are the wrong company number, a mistyped character, a code that has since been changed or cancelled, or a personal code entered by mistake. Work through the checks below before requesting a new code, because a replacement can take up to 10 working days.
Check the company number. The code only works with the company it was issued for. If you manage more than one company, it is easy to mix them up.
Check the characters. Look closely at similar letters and numbers, such as O and 0, or I and 1.
Check whether the code has changed. A director, accountant or former adviser may have changed or cancelled it in WebFiling. If a newer letter has arrived, use the code from that letter.
Check you are using the right code. The company code is 6 characters. A personal code from identity verification is a different code and cannot be used in its place. Software filers also need a separate presenter ID and presenter authentication code.
If none of these work, request a replacement and allow up to 10 working days.
Source: Company authentication codes for online filing (GOV.UK)
Keep your company authentication code safe
GOV.UK says to treat the code with the same care as your bank card PIN. Anyone who knows it can change your company’s details online. Only share it with someone you trust to file for you, such as your accountant.
Companies House cannot email the code or tell you it over the phone, and it will never call you to ask for it. If someone claiming to be from Companies House asks for the code, report it straight away. Companies House’s scams guidance says to forward suspicious emails to [email protected] and to contact Companies House about suspicious calls or letters.
Source: Reporting scams pretending to be from Companies House (GOV.UK)
How to change or cancel your authentication code
Sign in to Companies House WebFiling to change or cancel your company authentication code. You can change it to something more memorable, but GOV.UK says not to make it easy to guess, so mix letters and numbers.
Change it if someone you do not trust knows it, or if someone who is no longer authorised to file still has it, such as staff who have left or a previous accountant.
After a change, tell anyone else who files online for the company, such as your accountant. GOV.UK says they will not be able to use the old code once it has been changed.
Source: Company authentication codes for online filing (GOV.UK)
Common mistakes that cause delays
Leaving the request until the week of a deadline. The code comes by post and can take up to 10 working days, so there is no instant option.
Requesting a code to a registered office where nobody collects post. Fix the address problem first, or use the home address route if the company qualifies.
Filing something online just before using the home address route. A document filed online in the last 30 days stops the company using that service.
Confusing the company code with a personal code or a WebFiling sign-in. They are separate, and most filings need the right combination.
Forgetting to tell your accountant when the code changes. Their next filing will fail until they have the new one.
Ask SimpleFilings to request the code for you
You can request a code yourself through Companies House. GOV.UK does not list a fee for this. If you would rather we handle it, we check which route fits your company, then make the request for a £4.99 SimpleFilings service fee.
Companies House posts the code directly to the registered office or the officer’s home address. It does not come to us, so we never see it. If the registered office itself needs changing, we can help with that filing too once the code arrives.
Frequently asked questions
How long does a new Companies House authentication code take to arrive?
GOV.UK says it can take up to 10 working days. It is posted only, so request it well before any filing deadline.
Can Companies House email my authentication code or give it to me over the phone?
No. Companies House cannot email the code or tell it to you over the phone. It is posted to the registered office, or to an active officer’s home address through its home address service.
My authentication code was sent to our old address. What now?
If you cannot get post at the registered office, use Companies House’s service to send the code to an active officer’s home address, if the company qualifies. Once it arrives, update the registered office online.
Who can use the home address route?
It posts the code to an active officer’s home address that Companies House already holds. It cannot be used if the company filed a document online in the last 30 days, is not based in the UK, is not a limited company or LLP, or is dissolved.
Why is my authentication code not working?
Common reasons are the wrong company number, a mistyped character such as O for 0, or the code having been changed or cancelled in WebFiling. Make sure you are not using a personal code by mistake.
Can my accountant use our authentication code?
Yes, if you trust them to file for the company. GOV.UK says to share the code only with someone you trust to file information for your company. If you later change the code, tell your accountant, because GOV.UK says the old code cannot be used once it has been changed.
Is one authentication code used for all online filings?
Yes. The company uses the same authentication code to file through Companies House WebFiling, Find and update company information and commercial software. Software filers also need their own presenter ID and presenter authentication code.
How do I change my company authentication code?
Sign in to Companies House WebFiling and choose to change or cancel the code. Pick something memorable but hard to guess, then tell anyone else who files for the company, such as your accountant.
Is the company authentication code the same as my personal code?
No. The company code is 6 characters and belongs to the company. The personal code is issued to an individual when they verify their identity. Many filings need both.
Official sources
6
- Company authentication codes for online filing (GOV.UK)
- Send a company authentication code to an officer’s home address (Companies House)
- Change a company’s registered office address (AD01) (GOV.UK)
- Rules for a company’s registered office address (GOV.UK)
- Change your company’s address (GOV.UK)
- Reporting scams pretending to be from Companies House (GOV.UK)
Written and checked by SimpleFilings against these official pages. Last checked . SimpleFilings is operated by ONAF Limited (company number 12589383), an independent firm, not part of Companies House, HMRC or the government.