What is a payroll audit, and why is it important?

Every year, HMRC processes millions of PAYE submissions, and errors in payroll data are among the most common triggers for compliance checks. According to GOV.UK, penalties for inaccurate payroll reporting can reach up to 100% of the tax underpaid. This is why most businesses should conduct a payroll audit at least once a year to maintain accuracy and improve internal processes.

Whether you’re running your very first payroll audit or looking for some practical guidance, this guide explains how payroll audits work and how to carry them out effectively.

What is a payroll audit?

A payroll audit is the process of reviewing payroll data, processes, and calculations to ensure accuracy and compliance with UK law. Its main purpose is to identify errors, inconsistencies, or risks before they lead to penalties or employee disputes. 

In practice, this means checking that employees are paid correctly, deductions are accurate, and all reporting obligations are fulfilled. It acts as a safeguard, helping businesses maintain reliable payroll operations over time.

Why is a payroll audit important for UK businesses?

A payroll audit is important because it helps ensure compliance, reduce financial risk, and maintain trust with employees. Payroll affects every employee, and without regular checks, small errors can quickly become significant issues.

From a compliance perspective, HMRC requires accurate payroll reporting and record-keeping. Mistakes in tax deductions or late submissions can lead to penalties, including fines for inaccuracies, interest on unpaid tax and charges for late filing or payment. This is particularly the case where discrepancies appear in payroll data.

How does a payroll audit reduce compliance risks?

A payroll audit reduces compliance risks by identifying discrepancies in payroll data before they are flagged by HMRC. For example, inconsistent RTI submissions or incorrect tax codes are common triggers for audits and penalties.

By reviewing payroll regularly, businesses can correct these issues early and ensure all submissions are accurate and timely.

How does a payroll audit improve accuracy?

A payroll audit improves accuracy by verifying that all calculations and employee records are correct. This includes checking wages, deductions, and statutory payments.

Accurate payroll is essential not only for compliance but also for maintaining employee trust, as incorrect payments can quickly lead to disputes.

When should a payroll audit be conducted?

A payroll audit should be conducted regularly, with most UK businesses carrying out at least one audit per year. This ensures payroll processes remain accurate and aligned with current regulations.

More frequent audits may be necessary depending on the complexity of your payroll or changes within your organisation. For example, rapid growth, system changes, or updates to payroll legislation can all introduce new errors into your processes. Running an audit during these periods helps ensure your payroll remains accurate and compliant despite these changes.

How do you conduct a payroll audit?

A payroll audit is conducted by reviewing employee data, payroll calculations, and HMRC submissions through a structured process. The goal is to ensure consistency, accuracy, and compliance across all payroll activities.

What are the key steps in a payroll audit?

1. The first step is reviewing employee data to ensure all records are accurate and up to date. This includes checking tax codes, contractual details, and personal information.

2. Next, payroll calculations should be verified to confirm that gross pay, deductions, and net pay are correct. Any discrepancies should be investigated and corrected.

3. You should then compare payroll records with HMRC submissions to ensure consistency. This step is crucial for identifying reporting errors that could lead to compliance issues.

4. Finally, reviewing internal processes and controls helps ensure that payroll data is secure and that errors are less likely to occur in the future.

Example: If payroll records show different figures from RTI submissions, this may indicate a reporting error that needs immediate correction.

What does a payroll audit include?

A payroll audit reviews all key payroll components to ensure they are correct and up to date. This usually includes employee data, tax codes, pay calculations, and statutory deductions such as National Insurance and pensions.

It also involves checking submissions to HMRC, ensuring reported figures match internal payroll records. Reviewing benefits, expenses, and employee classifications is equally important, as payroll errors can trigger compliance issues. 

What are the most common payroll audit errors?

Common payroll audit errors typically relate to incorrect data, miscalculations, or reporting inconsistencies. While often small, these errors can lead to significant compliance risks over time.

One of the most frequent issues is the use of incorrect or outdated tax codes, which can result in employees paying too much or too little tax. Misclassifying workers is another common error, particularly when distinguishing between employees and contractors. In addition, pension auto-enrolment errors are increasingly flagged during audits, particularly where eligible employees have not been enrolled on time or contributions have been calculated on the wrong earnings basis.

Inaccurate reporting to HMRC is also a key risk, especially when submissions are late or do not match payroll records. These discrepancies are often flagged during compliance checks.