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Companies House guide

What is a company authentication code?

The company authentication code is the Companies House code used to authorise online filings for a specific company.

Last reviewed
18 July 2026
Sources checked
18 July 2026
Reading time
5 minutes

Written by Business Sorted editorial team

Business Sorted provides general educational information and organisation tools. It is not Companies House, HMRC, a solicitor, an accountant, a tax adviser or a regulated professional adviser. Check official sources and get professional advice where your circumstances need it.

Direct answer

A company authentication code is a 6-character alphanumeric code issued by Companies House to each company. Companies House says it is used to authorise information filed online and is equivalent to a company officer’s signature.

Key facts

  • The company authentication code is a 6-character alphanumeric code.
  • It authorises online filings for the company.
  • It is different from a personal code for identity verification.
  • Companies House says it can take up to 10 working days to receive a requested code.

What the code is

Companies House says the company authentication code is issued to each company and is used to authorise online filings. It is different from a Companies House personal code used for identity verification.

You may need the code for Companies House WebFiling, Find and update company information, or commercial software filing.

Why security matters

Companies House guidance says the code should be treated with the same care as a bank card PIN. Anyone who knows it may be able to change company details online.

Share it only with people you trust to file for the company, and change it if it is known by someone who should no longer have filing access.

Plan for filing deadlines

Do not wait until accounts or a confirmation statement are due before checking whether you have access. Companies House says delivery of a requested authentication code can take up to 10 working days.

A missing code can turn a simple filing into a deadline risk, especially near accounts or confirmation statement dates.

Frequently asked questions

Is the company authentication code the same as a Government Gateway login?

No. Companies House guidance says you cannot use your Government Gateway account to send Companies House information online.

Should I email the authentication code to other people?

Be careful. Companies House says to share the code only with someone you trust to file information for your company.

Related guides

How to get or replace a Companies House authentication codeLearn how Companies House sends company authentication codes, how long delivery can take and what to check if the code is missing.How to file a confirmation statementLearn the usual steps for filing a Companies House confirmation statement and what UK directors should check before they submit it.How to change a company's registered office addressLearn when and how to tell Companies House about a change to a limited company's registered office address.Companies House deadlines explainedA plain-English overview of the main Companies House deadlines UK limited-company directors should track and how they differ from HMRC dates.

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