Companies House Authentication Code: What It Is & How to Get It
Your Companies House authentication code is one of the most important security tools for your business. Without it, you can’t file accounts, update company information, or make changes to directors. In this guide, we’ll explain what the authentication code is, why it matters, how to get it, and what to do if you’ve lost or need to change it.
What Is a Companies House Authentication Code?
The authentication code is a unique six-character alphanumeric code issued by Companies House. Think of it as a digital signature or password for your company. It proves that the person filing online is authorised to act on behalf of the company.
It’s important to treat the authentication code like a PIN. Anyone who has access to it can update your company’s public record, so it should be stored securely and shared only with trusted individuals such as your accountant or company secretary.
Why the Authentication Code Matters
You’ll need your Companies House authentication code to make almost all filings online, including:
Filing your company’s confirmation statement
Submitting annual accounts
Changing or appointing directors and secretaries
Updating your registered office address
Reporting changes to Persons with Significant Control (PSC)
Allotting new shares
Changing your company’s accounting reference date
If you don’t have your code, you can’t submit these forms electronically and will have to use slower paper filing.
How to Get a Companies House Authentication Code
When your company is first incorporated
When you register a new company, Companies House issues the authentication code automatically. It’s sent by post to the company’s registered office address, usually within a few working days of incorporation.
If you’ve lost or never received your code
If you don’t have your code or can’t find it, you can request a reminder online using Companies House WebFiling. A new copy will be posted to your registered office address. In some circumstances, it may be sent to a director’s home address, but this isn’t always available.
Delivery typically takes up to five working days, although it may take longer at busy times.
If your registered office is incorrect
If your registered office address is wrong, the code will be posted to the incorrect location. You’ll need to update the address with Companies House before requesting a new code.
How to Use the Authentication Code
Once you have the code, you can use it to:
Sign in to WebFiling and submit company information
Authorise your accountant or company formation agent to file on your behalf
File through approved third-party software
After entering it once in WebFiling, the system usually stores your company details so you don’t need to re-enter it for every filing.
How to Change or Cancel Your Authentication Code
You may want to change your code if you believe it’s been compromised, or simply as a good security practice.
Change your code: Log in to WebFiling, go to “Company Authentication” and select a new six-character alphanumeric code. Your old code will immediately stop working.
Cancel your code: If you no longer wish to file online, you can cancel it via WebFiling. However, this is rare and not recommended as it limits filing to slower paper forms.
If you change or cancel the code, remember to update anyone who needs it — such as your accountant.
Security Best Practices
Because the authentication code controls your company filings, it’s important to use it safely:
| Best Practice | Why It Matters |
|---|---|
| Keep the code confidential | Anyone with the code can make changes to your company record |
| Change the code if compromised | Prevents unauthorised access to company filings |
| Choose a secure code | Avoid obvious codes — use a mix of letters and numbers |
| Store it securely | Don’t keep it in unprotected documents or emails |
| Watch out for scams | Companies House will never ask for your code by phone or email |
Common Problems and Solutions
| Problem | Likely Cause | Solution |
|---|---|---|
| Code hasn’t arrived | Postal delay or wrong address | Wait a few days, check registered office address, request again |
| Code doesn’t work | Mistyped or changed | Double-check, or request a new one |
| Can’t request to director’s home | Address not eligible | Use the registered office instead |
| Accountant can’t file | Old code in use | Provide them with the updated code |
Future Changes: Personal Codes and Identity Verification
From late 2025, Companies House is introducing new rules requiring directors and Persons with Significant Control (PSC) to verify their identity using personal codes. These will be separate from the company authentication code and will add another layer of security.
This means that in the future, you may need both:
The company authentication code to authorise company filings
A personal code linked to your identity as a director or PSC
Frequently Asked Questions
Can I file to Companies House without the authentication code?
No, you need the code to make online filings. Without it, you’ll be limited to paper submissions.
How long does it take to get a code?
Usually up to five working days, but it may take longer at busy times.
Can multiple companies share the same code?
Each company has its own code. However, you can choose to set the same code across different companies you manage — although for security, unique codes are safer.
What happens if I change my registered office address?
The code will be sent to the new address once the change is registered. Always ensure your company records are up to date.
What’s the difference between the authentication code and the new personal code?
The authentication code belongs to the company and is used for filings. The personal code will belong to you as an individual director or PSC, and is used to verify your identity.
Why Trust This Guide
This page has been written and reviewed by professionals with experience in company formation, statutory compliance, and corporate governance. It reflects current Companies House rules and upcoming legal changes, making it a reliable and practical resource for business owners and directors.
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