Tax Office Reference Number Guide

Employers work with a range of HMRC identifiers, but few are as central to payroll and compliance as the tax office reference number, formally known by HMRC as the employer PAYE reference. It underpins how HMRC recognises the employer, processes payroll submissions, allocates PAYE liabilities and manages correspondence. When HR and payroll teams do not have the correct reference to hand, day-to-day processes slow down, errors are more likely and HMRC interactions become more difficult than necessary.

The reference appears routinely in employer-facing documentation yet remains a point of confusion, particularly for organisations with multiple PAYE schemes, legacy payroll systems or recently restructured business groups. Employers and HR professionals also encounter similar terminology, including references to the HMRC office number and the separate accounts office reference used for PAYE payments. Understanding what the number represents, how it is formatted and where to find it supports clean payroll administration and reduces the risk of avoidable HMRC issues.

What this article is about
This article provides employers and HR professionals with a clear and detailed explanation of the tax office reference number (employer PAYE reference). It explains how the number is structured, where it is located, how HMRC uses it and why it matters for payroll compliance. It also clarifies how the employer PAYE reference differs from the separate accounts office reference that employers must use when making PAYE payments. In addition, the article covers what to do if details change or if an employer needs to amend their records with HMRC, including how to confirm the correct reference via the HMRC Business Tax Account. The aim is to help HR teams handle payroll queries confidently and ensure the organisation’s PAYE processes remain accurate and compliant.

Section A: Understanding the tax office reference number

Every employer registered for PAYE is assigned a specific tax office reference number by HMRC. Formally, HMRC refers to this as the employer PAYE reference, but in practice employers, HR teams and payroll providers often call it the “tax office reference” or “PAYE reference”. HR and payroll teams use this identifier whenever they deal with HMRC about PAYE, National Insurance, tax codes or employee payroll details. Although the reference is widely used, confusion often arises because different terms circulate in practice, including “employer reference”, “tax district number” and references to the HMRC office number. Section A sets out what the reference is, how it is structured and how HMRC uses it to administer the employer’s PAYE obligations.

The reference aligns HMRC’s internal systems with the employer’s payroll submissions. Without this identifier, HMRC cannot match payments, cannot allocate liabilities accurately and cannot process payroll data coming through RTI. For employers, understanding the components of the reference helps prevent misfiling errors and reduces the risk of HMRC mismatches. It is also important to distinguish the employer PAYE reference from the separate accounts office reference issued by HMRC, which is used specifically to allocate PAYE payments rather than to identify RTI submissions.

1. What the tax office reference number is

The tax office reference number is the unique identifier assigned to an employer’s PAYE scheme. It links the employer to the HMRC office responsible for handling their PAYE affairs. HMRC issues the number when an employer registers for PAYE and it remains the primary reference for most payroll-related interactions.

The reference is often referred to interchangeably with the PAYE reference because both elements together form the standard employer PAYE reference. For practical purposes, employers and HR teams use the full reference to ensure HMRC can locate and update the correct PAYE account.

Employers with more complex structures, such as groups with multiple payrolls or entities, may have several references. Each PAYE scheme will be assigned its own tax office reference number, ensuring HMRC can track liabilities for each distinct part of the business. This is separate from the accounts office reference, which HMRC issues to identify the employer’s PAYE payment account and which must be used as the payment reference when remitting PAYE and National Insurance to HMRC.

2. Format of the number

The reference is made up of two parts:

• The tax office number (a three-digit code identifying the HMRC office)
• The employer PAYE reference (the individual employer identifier assigned by HMRC)

Together, these form the full reference, usually written as: 123/AB456 (example format).

The first part tells HMRC which tax office manages the employer’s PAYE scheme. The second part uniquely identifies the employer within that tax office’s records. HR and payroll professionals need to use both parts whenever communicating with HMRC or filing RTI submissions.

For employers operating more than one PAYE scheme, each scheme will have a different second part of the reference. This helps HMRC distinguish payroll liabilities, even when the tax office number remains the same. The accounts office reference, by contrast, has a different format and is used when making PAYE payments to HMRC, so employers must ensure they use the correct identifier in the correct context.

3. How HMRC uses the number in payroll

HMRC relies heavily on the tax office reference number to process PAYE submissions and track employer liabilities. It is used to:

• Match RTI submissions (FPS and EPS) to the correct employer records
• Allocate PAYE tax and National Insurance contributions to the appropriate PAYE scheme
• Process amendments, corrections and late submissions
• Identify the correct employer account when issuing tax code changes, reminders and notices

If the reference is provided incorrectly, HMRC may not associate payroll submissions or related data with the correct account. This can trigger automated late filing or late payment notices, underpayment warnings or follow-up compliance queries, even when the employer has met their obligations. Under the RTI regime, late or mismatched FPS filings can give rise to late filing penalties where HMRC records show that returns are missing or incorrectly submitted.

It is equally important for employers to use the correct accounts office reference when making PAYE payments, as HMRC uses that separate identifier to allocate payments to the correct account. Using the wrong identifier for submissions or payments can create discrepancies that take time and evidence to resolve.

Section A Summary
The tax office reference number, formally the employer PAYE reference, links the employer’s PAYE scheme to the correct records within HMRC. Employers must use the full reference, including both the tax office number and the PAYE employer reference, in all relevant payroll submissions and correspondence. Distinguishing this reference from the separate accounts office reference used for PAYE payments is critical. Understanding how the number is structured and where it fits into HMRC processes reduces the risk of errors, protects against RTI mismatches and keeps payroll operations compliant.

Section B: Where employers find their tax office reference number

HR and payroll teams need reliable access to the tax office reference number to manage PAYE reporting accurately. Although the reference is assigned once the employer registers for PAYE, it appears across several HMRC documents, payroll systems and online employer accounts. Section B explains where employers can locate the reference, how to check it is correct and when variations may indicate multiple PAYE schemes or legacy records.

The reference must be used consistently. If payroll uses an incorrect or outdated reference, HMRC may treat submissions as mismatched or unallocated, leading to avoidable correspondence or payment queries. Ensuring all payroll systems, staff and external payroll providers use the correct number supports clean administration and helps HR respond effectively to employee or HMRC queries.

1. HMRC communications

HMRC includes the employer PAYE reference in most correspondence relating to PAYE obligations. Common sources include:

• The PAYE registration letter issued when the employer first sets up its PAYE scheme
• Tax code notices and PAYE updates
• Payment reminders and PAYE account statements
• Penalty notices or late filing notifications
• Digital notices issued through the employer’s HMRC Business Tax Account

Historically, HMRC issued P30B payment reminders, although RTI has reduced reliance on this format. Employers may still receive reminders but should expect most PAYE communications to be delivered digitally. Each PAYE scheme receives separate correspondence displaying its own employer PAYE reference.

2. Payroll software and payroll records

Payroll systems require the employer PAYE reference to generate RTI submissions. The reference can usually be found within:

• Employer settings or company configuration menus
• RTI filing settings and PAYE scheme details
• Year-end summaries and RTI reports such as FPS and EPS summaries

If a payroll migration has recently occurred, or if the employer has changed payroll providers, it is important to confirm that the correct reference has been transferred. Legacy or outdated references may appear in archived data or historical reports. HR teams should ensure that payroll systems use the live PAYE reference, and external payroll bureaux must also update their records to prevent RTI submissions being filed under the wrong scheme.

Payroll reporting tools provide a straightforward way to verify that the reference being used matches the employer’s current HMRC documentation. Regular checks support payroll governance and avoid HMRC discrepancies.

3. Employee documents

Although the employer PAYE reference does not always appear on employee documents, some employers configure their payroll systems to include it on:

• Payslips
• P60s
• Payslip summaries

Its inclusion depends on payroll software settings. The absence of the reference on payslips or P60s does not indicate a problem. HR teams should not rely solely on employee-facing documents to locate the reference.

Where it is displayed, the number can help employees when contacting HMRC about their tax records, especially if HMRC requests confirmation of the employer’s PAYE details. HR teams should, however, direct staff to use the Accounts Office Reference when making enquiries about PAYE payment allocations, as this is a separate identifier.

Section B Summary
Employers can find their tax office reference number on HMRC correspondence, within payroll software, on certain employee documents and through the HMRC Business Tax Account. HR teams should verify that the number used in payroll settings matches HMRC’s current records, especially following payroll migrations or business changes. Ensuring all internal systems and external payroll providers use the correct employer PAYE reference supports accurate RTI submissions and reduces the risk of HMRC discrepancies.

Section C: Why the tax office reference number matters for employers

The tax office reference number, formally the employer PAYE reference, is fundamental to PAYE administration. It enables HMRC to process payroll submissions, reconcile liabilities and manage employer communications without delay. When the reference is incorrect or inconsistently applied across payroll systems, the employer’s PAYE account can become misaligned, creating administrative problems that HR teams must then resolve. Section C explains why the reference is essential for legal compliance, operational accuracy and effective employee support.

For employers, the reference acts as a safeguard. It ensures that PAYE data reaches the correct account and that payments, tax code updates and adjustments apply to the right payroll scheme. A missing or incorrect reference disrupts this chain and introduces risks that may escalate into HMRC interventions or employee-facing issues. Understanding its significance helps HR teams maintain strong payroll governance and avoid compliance exposure.

1. PAYE reporting compliance

HMRC’s Real Time Information (RTI) framework relies on the employer PAYE reference to match submissions to the correct employer account. The reference is used on:

• Full Payment Submissions (FPS) reporting employee pay and deductions
• Employer Payment Summaries (EPS) reporting adjustments, statutory payments and variations
• Starter and leaver notifications
• Tax code updates and employee PAYE changes

If the reference is incorrect, HMRC’s systems may reject or misallocate FPS or EPS submissions. This may create the appearance of missing filings even when payroll has submitted them correctly. Under the RTI penalty regime, HMRC may issue late filing or non-filing notices where its records show incomplete returns. These penalties may arise solely from mismatches caused by the wrong employer PAYE reference being used.

Accurate use of the reference ensures that HMRC recognises each submission as belonging to the employer’s PAYE scheme, which is a central requirement of PAYE compliance.

2. Avoiding HMRC mismatches and penalties

Using an incorrect or outdated employer PAYE reference can cause payments and submissions to appear missing or underreported. HMRC may then issue:

• Late payment notices
• Underpayment demands
• Interest charges
• Compliance warnings or penalty letters

These issues may arise even where the employer has paid correctly, simply because HMRC cannot reconcile the transactions with the correct PAYE scheme. For employers with multiple PAYE schemes, the risk is higher. A payment intended for one scheme may be applied to another if references are mixed up, leading to discrepancies such as one account showing an overpayment and another showing an apparent debt.

Employers must also distinguish between the employer PAYE reference and the separate accounts office reference. The latter must be used as the payment reference when making PAYE payments. Using the wrong reference for payments or filings can trigger mismatches that require manual intervention to resolve.

3. Employee queries and statutory processes

HMRC may need to verify an employer’s PAYE details when reviewing an employee’s tax position or entitlement to certain statutory payments. When HR cannot provide the correct employer PAYE reference promptly, the process delays the employee’s outcome and may require HMRC to undertake additional checks.

The reference also supports employees with:

• Tax code corrections
• HMRC employment record updates
• National Insurance contribution queries
• Mortgage or financial reference checks

Lenders and financial institutions occasionally request the employer’s PAYE reference as part of employment verification. Having the correct reference available enables HR to respond promptly and maintain service levels for staff.

Section C Summary
The tax office reference number underpins accurate PAYE reporting, correct allocation of HMRC payments and efficient management of employee tax-related queries. Incorrect or inconsistent use increases the risk of HMRC mismatches, RTI penalty notices and administrative delays. For employers and HR teams, maintaining accurate use of the employer PAYE reference protects payroll integrity, reduces compliance exposure and supports employees effectively.

Section D: Correcting, updating or replacing a tax office reference number

Employers occasionally need to update or replace their tax office reference number due to structural changes, new PAYE schemes or administrative updates within HMRC. HR and payroll teams must handle these changes carefully to avoid disrupting payroll submissions or triggering unnecessary HMRC queries. Section D explains when a reference may change, how to update HMRC and what internal controls employers should maintain to keep their PAYE records accurate.

If details are not updated promptly, HMRC systems may continue to expect RTI submissions under the previous reference. This can lead to duplicate records, incorrectly allocated liabilities or compliance notices, even where the employer is meeting all obligations. Ensuring all systems, staff and external payroll bureaux reflect the new reference is essential for operational continuity and compliance.

1. When the number changes

The employer PAYE reference remains consistent unless the employer’s PAYE arrangements change. Common reasons for changes include:

• Setting up an additional PAYE scheme for different employee groups or business units
• Business restructuring or transfers that move liabilities to a different PAYE scheme
• Mergers or acquisitions leading to consolidation or separation of payroll operations
• HMRC administrative reallocations, where PAYE schemes are transferred between HMRC offices

HMRC may reassign PAYE schemes as part of internal regional restructuring. Employers do not choose their HMRC tax office; it is allocated by HMRC’s internal administrative structure. A change of HMRC office does not automatically create a new PAYE scheme, but HMRC may issue an updated reference depending on the nature of the reallocation.

2. How to update HMRC

If an employer becomes aware that its PAYE details are incorrect or out of date, they should contact HMRC’s employer helpline or write to the tax office shown on recent correspondence. Employers will normally need to provide:

• The full employer PAYE reference
• The employer name and PAYE scheme details
• A description of the issue or the change requested
• Supporting evidence where applicable

HMRC will confirm updates and issue written notification if a new reference is required. Once issued, HR and payroll teams must update:

• Payroll software configuration
• RTI filing settings for FPS and EPS submissions
• Internal payroll policies and documentation
• All external payroll bureaux or bookkeeping providers

Employers should note that PAYE payments to HMRC must always use the separate Accounts Office Reference, which does not automatically change when the employer PAYE reference changes. Using the wrong reference for payments may cause allocation errors and reconciliation delays.

3. Record-keeping & HR governance

Accurate record-keeping helps employers maintain compliance and avoid delays when dealing with HMRC. HR and payroll teams should:

• Store all HMRC correspondence securely and keep scheme-level files
• Maintain clear internal documentation for each PAYE scheme
• Keep a log of all changes to employer PAYE references
• Ensure payroll staff and external providers are informed promptly of any updates
• Carry out periodic payroll audits to confirm that the correct employer PAYE reference is used across all systems

Where employers operate multiple PAYE schemes, strong documentation and clear governance reduce the risk of filing RTI submissions or making payment allocations using the wrong reference. Maintaining accuracy ensures payroll remains compliant, resilient and efficient during organisational change.

Section D Summary
Employers may need to update or replace their employer PAYE reference following changes to PAYE schemes, mergers or HMRC administrative reallocations. Keeping records up to date, informing HMRC promptly and ensuring payroll systems and external providers use the correct reference helps avoid mismatches and RTI submission errors. Strong internal governance and periodic checks support compliance and protect payroll accuracy.

FAQs

These FAQs address the questions HR teams and employers most commonly encounter when dealing with employer PAYE references. They provide practical guidance to support accurate payroll administration and efficient HMRC interactions.

Is a tax office reference number the same as a PAYE reference?

The terms are often used interchangeably. Formally, HMRC refers to the number as the employer PAYE reference. It combines the tax office code and the employer’s unique PAYE identifier. This reference is distinct from the separate Accounts Office Reference, which is used when making PAYE payments.

Can an employer have more than one tax office reference number?

Yes. Employers with multiple PAYE schemes, separate business divisions or group structures may be assigned several references. Each PAYE scheme is administered separately within HMRC’s systems and therefore has its own employer PAYE reference.

What happens if payroll submits RTI filings using the wrong reference?

HMRC may be unable to match the submission to the correct employer account, causing apparent late filings or missing payments. Employers may receive automated warnings or late filing penalties where HMRC records show incomplete submissions. HMRC may require evidence to reallocate payments or correct mismatches.

Does the reference change if the employer changes address?

Not automatically. A change of business address does not usually affect the employer PAYE reference. However, if HMRC reallocates the PAYE scheme to a different administrative office, it may issue a new reference depending on the nature of the reallocation.

How quickly does HMRC update changes to a reference?

Timeframes vary. Some changes are processed within days, while others require manual review and may take several weeks. Employers should continue using the existing employer PAYE reference until HMRC confirms any change in writing.

Conclusion

The tax office reference number, formally the employer PAYE reference, sits at the centre of an employer’s PAYE obligations. It ensures HMRC can identify the correct PAYE scheme, process RTI submissions, allocate payments and issue accurate correspondence. When the reference is wrong, incomplete or inconsistently applied across payroll systems, employers face unnecessary compliance risks and administrative complexity. HR and payroll teams therefore need to know where the reference appears, how it is structured and when it may change.

Clear internal governance, accurate record-keeping and consistent use of the reference strengthen payroll reliability and support smoother interactions with HMRC. For organisations with multiple PAYE schemes or recent structural changes, periodic checks and payroll audits help ensure the correct reference is used in all systems. Ensuring all staff and third-party payroll providers apply the correct employer PAYE reference protects the business from avoidable RTI warnings, payment mismatches and delays to employee queries.

A disciplined approach to maintaining and verifying the employer PAYE reference contributes directly to stronger compliance outcomes and more resilient payroll operations.

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