Company authentication codes for online filing
Source: gov.uk (2025-08-26)

How to request and manage the company authentication code you'll need to file information online at Companies House.

The company authentication code is a 6 digit alphanumeric code issued by Companies House to each company. The code is used to authorise information filed online and is the equivalent of a company officer’s signature.

You’ll need a company authentication code to file your information online (https://www.gov.uk/guidance/filing-your-companies-house-information-online) or file using commercial software (https://www.gov.uk/software-company-accounts).

The company authentication code is different to the Companies House personal code (https://www.gov.uk/guidance/verifying-your-identity-for-companies-house#what-happens-when-you-verify) which is issued to individuals when they verify their identity.

Do not wait until your accounts are due to request your company authentication code. Delivery could take longer than usual during busy periods.

How to get your company authentication code

To request a code, you’ll need to create an account or sign in to Companies House WebFiling (https://idam-ui.company-information.service.gov.uk/) and follow the steps.

We’ll send your code by post to your company’s registered office - it can take up to 10 working days to arrive. If your company already has a code, we’ll send you a reminder.

If you cannot access your company’s registered office address, we can send your authentication code to your home address instead (https://find-and-update.company-information.service.gov.uk/auth-code-requests/start).

We cannot send your company authentication code by email or tell you the code over the phone.

Using your code

You’ll use the same company authentication code for your company to file online using:
- Companies House WebFiling (https://idam-ui.company-information.service.gov.uk/)
- Find and update company information (https://find-and-update.company-information.service.gov.uk/)
- commercial software (https://www.gov.uk/software-company-accounts)
To use commercial software, you’ll need to set up an online filing account (https://www.gov.uk/government/publications/apply-for-a-companies-house-online-filing-presenter-account) to get a presenter ID and presenter authentication code.

You cannot use your Government Gateway account to send Companies House information online.

Changing or cancelling your code

Sign in to Companies House WebFiling (https://idam-ui.company-information.service.gov.uk/) to change or cancel your code. You can change your code to something more memorable, but do not make it easy to guess.

You must tell anyone else who files online for your company (such as an accountant) if you change your code. They will not be able to use the old company authentication code once it has been changed.

Looking after your code

You should treat your company authentication code with the same care as your bank card PIN. Anyone who knows your code is able to change your company’s details online.

To look after your company authentication code:
- mix letters and numbers so your code is not easy to guess
- only share your code with someone you trust to file information for your company
- change your code if it’s known by someone you do not trust
- change your code if it’s known by someone who’s no longer authorised to file for your company (such as staff who’ve left your company, or your previous accountant)
We’ll never ask you what your company authentication code is over the phone.

If you’re contacted by someone who asks for your code and claims to be from Companies House, you should report fraud to Companies House (https://www.gov.uk/government/publications/reporting-fraud-about-a-company-to-companies-house/reporting-fraud-to-companies-house) immediately.