What Is an Employer’s PAYE Reference Number (ERN)?

An Employer Reference Number (ERN) — also known as a PAYE Reference — is a unique code issued by HMRCwhen a business registers as an employer in the UK. It identifies your company for tax and payroll purposes. The ERN appears on payslips, P45s, and P60s and is used when submitting PAYE information, paying tax, or taking out employers’ liability insurance.

Why the Employer Reference Number Matters

If you employ staff or pay yourself through PAYE, you need an Employer Reference Number. It’s how HMRC recognises your business when you send employee tax and National Insurance information.
Without it, you can’t legally process payroll or report PAYE deductions. It’s also required for employers’ liability insurance and when employees need to prove employment to lenders or government agencies.
In short: no ERN, no payroll.

What Is an Employer Reference Number (ERN)?

An Employer Reference Number (ERN) is the unique identifier HMRC gives you once you register as an employer. It’s sometimes called a PAYE reference number or HMRC employer reference.

It usually looks like this:
123/AB45678

• The first part (123) identifies your tax office.
• The second part (AB45678) identifies your business within that office.

👉 It’s different from your Accounts Office Reference (used to pay HMRC) or Unique Taxpayer Reference (UTR), which relates to your business or self-assessment, not payroll.

Who Needs an Employer Reference Number?

You’ll need an ERN if you:

• Pay employees (including yourself as a director) through PAYE
• Deduct income tax or National Insurance contributions
• Provide employee benefits or expenses (even for directors only)
• Hire casual, part-time, or full-time staff

You don’t need an ERN if you’re a sole trader with no employees or pay below the PAYE threshold (£123 per week as of 2025).

How to Register and Get Your ERN

To get your Employer Reference Number, you must register as an employer with HMRC — ideally before your first payday.
Here is how it works:

1. Go to GOV.UK: Register as an employer.
2. Enter your company details, start date, and employee information.
3. HMRC will send your ERN and Accounts Office Reference within 5–10 working days (usually faster if registered online).
4. Once received, use it on all PAYE submissions, payslips, and HMRC correspondence.

 If you use Persona Finance for payroll setup, we can register you and handle the HMRC process from start to finish.

Where to Find Your ERN

You will find your Employer Reference Number on:

• HMRC welcome letter (after registration)
• PAYE correspondence from HMRC
• Employee payslips
• P45, P60, or P11D forms
• Employer’s liability insurance certificate
• Your company’s online PAYE account

If you lose it, check these documents or contact HMRC’s Employer Helpline.

How Your ERN Is Used

Your ERN is required in several areas of your business:

• Payroll & RTI submissions: Every Real Time Information (RTI) submission to HMRC includes your ERN.
• Payslips & P45/P60s: Appears on employee tax documents for identification.
• Employers’ liability insurance: Insurers must record your ERN on the policy to link with the Employers’ Liability Tracing Office (ELTO) database.
• Government communications: Used in all HMRC correspondence, audits, and employee benefit claims.

Common Mistakes to Avoid

Even experienced employers sometimes get caught out. Avoid these errors:

• ❌ Confusing your ERN with your Accounts Office Reference or UTR.
• ❌ Forgetting to include the ERN on payslips or insurance certificates.
• ❌ Using the wrong ERN after changing your PAYE scheme.
• ❌ Not registering for PAYE early enough before the first payday.

👉 Always keep your ERN safe — ideally in your payroll software and accounting records.

FAQs

Yes — “Employer Reference Number” and “PAYE reference” refer to the same thing.

Can a business have more than one ERN?
Yes. Large businesses or those with multiple PAYE schemes can have more than one.

What if I lost my ERN?
Check old HMRC letters, payslips, or P60s. If you can’t find it, call the HMRC Employers’ Helpline.

Do sole traders need an ERN?
Not unless they employ staff or pay above the PAYE threshold.

Is the ERN used for insurance?
Yes. Every employers’ liability insurance policy must show your ERN.

Conclusion

The Employer Reference Number (ERN) is essential for payroll, insurance, and tax compliance in the UK. Without it, you can’t pay employees, report to HMRC, or meet your legal duties as an employer.
At Persona Finance, we help UK businesses register with HMRC, obtain their ERN, and manage ongoing PAYE compliance with ease.
👉 Need help registering for an ERN or managing payroll?

Contact Persona Finance — we will handle the setup, compliance, and submissions for you.