What is a payroll system and how does it work in the UK?

From 6 April 2026, the Employment Rights Act 2025 gives every employee day-one Statutory Sick Pay and adds a separate duty to keep holiday pay records for six years, on top of HMRC's existing three-year PAYE retention rule. With HMRC's compliance work generating a record £48 billion in additional tax revenue in 2024/25, a reliable payroll system is the simplest way to keep PAYE, RTI and statutory pay accurate while meeting these new obligations.

What is a payroll system?

A payroll system is a process, service or software used to calculate employee pay, apply deductions and ensure compliance with HMRC regulations.

It allows employers to:

• Calculate gross-to-net pay 

• Deduct Income Tax and National Insurance

• Manage pensions and statutory payments 

• Generate payslips 

• Report payroll data to HMRC 

👉 To note: Automated payroll systems significantly reduce calculation errors and free up admin time, helping employees be paid accurately and on time.

How does a payroll system work in the UK?

A payroll system works by collecting employee data, calculating pay and deductions, and reporting this information to HMRC through Real Time Information (RTI).

1. Collect employee information

Employers gather key payroll data, including:

• Salary or hourly pay 

• Tax code 

• Contracted hours 

• Pension details

2. Calculate pay and deductions

The system calculates:

• Gross pay 

• Income Tax and NICs 

• Pension contributions 

• Other deductions (e.g. student loans) 

3. Generate payslips

Payslips are produced showing:

• Earnings 

• Deductions 

• Net pay

4. Submit RTI reports to HMRC

Payroll data is submitted via Full Payment Submission (FPS) on or before each payday. Additionally, an Employer Payment Summary (EPS) must be submitted by the 19th of the following month if no employees were paid or to recover statutory credits.

5. Pay employees and HMRC

Employers:

• Pay employees their net salary 

• Pay HMRC the deducted tax and NICs

What types of payroll systems are available?

There are three main types of payroll systems: manual (in-house), outsourced payroll and software-based.

Manual payroll

Manual payroll involves calculating pay and deductions using spreadsheets or manual processes.

• Low cost but prone to errors 

• Time-consuming and difficult to scale 

Outsourced payroll

Outsourcing involves delegating payroll to an external provider.

• Reduces administrative workload 

• Provides access to payroll expertise 

Payroll software

Payroll software automates payroll calculations and compliance tasks.

• Reduces errors and saves time 

• Automatically updates tax rates and legislation

Payroll system comparison table

What are the key features of a payroll system?

A payroll system includes features designed to simplify payroll and ensure compliance.

Key features include:

• Automatic tax and NIC calculations

• RTI submissions to HMRC (FPS and EPS)

• Payslip generation

• Pension auto-enrolment management

• Statutory pay handling (SSP, SMP, SPP, SAP)

• Reporting and analytics

• HMRC-recognised compliance updates

How can payroll software improve compliance?

Payroll software improves compliance by automating calculations, applying updated tax rules and ensuring timely submissions to HMRC.
By integrating automated safeguards, software significantly reduces human error in complex calculations, ensuring that RTI deadlines are met through scheduled, direct-to-HMRC submissions. These systems automatically apply current tax rates and legislative changes (such as Student Loan Plan 5) as soon as they take effect, removing the need for manual updates. Furthermore, software creates a robust, searchable digital trail to maintain accurate payroll records, ensuring your business meets retention rules (3 years for PAYE, 6 years for holiday pay records under ERA 2025).

The best payroll software solutions are HMRC-recognised, which guarantees the system is tested and capable of performing all mandatory RTI tasks correctly.

How do you choose the right payroll system?

Choosing the right payroll system or software depends on your business size, complexity and operational needs.

Key factors to consider are:

• Number of employees 

• Payroll frequency 

• Budget 

• Compliance requirements 

• Integration with HR or accounting systems 

👉To note: Before comparing solutions, it’s important to understand what your business needs most and which features to prioritise when identifying the right payroll software.

How can you optimise your payroll system?

Optimising your payroll is no longer just about speed; it is about building an automated workflow that protects your business from the wider remit of the new Fair Work Agency.

⚠️ Warning: since 6 April 2026, late RTI filings can trigger automatic monthly fines from £100 (1–9 employees) to £400 (250+), even before HMRC investigates the cause (GOV.UK – PAYE late filing penalties).

Prioritise data accuracy and digital validation

Accurate data is the foundation of any reliable system. Instead of simply updating records, you should implement automated validation to check tax codes and salaries before processing. This proactively catches high-risk errors, such as incorrect Student Loan Plan 5 flags or National Minimum Wage breaches (£12.71/hour for workers aged 21+ from April 2026) that often trigger automated HMRC penalties.

Embrace strategic automation and real-time filing

Automation removes the human intervention that leads to compliance gaps. HMRC-recognised software links directly to HMRC for automatic RTI submissions, ensuring your Full Payment Submissions (FPS) are sent "on or before" payday. This shift eliminates the risk of automated monthly fines, which now range from £100 to £400 depending on your headcount.

Enhance payslip transparency and trust

Clear, digital payslips significantly reduce administrative burden by cutting down on employee queries. An optimised system provides a detailed breakdown of earnings, pension contributions, and tax paid. Including real-time leave balances on payslips also helps employees manage their time off, reducing the operational risk of year-end holiday bottlenecks.

Proactive compliance and legislative agility

Your system must be configured to the latest 2026/27 tax year thresholds and adjusted whenever the HMRC Employer Bulletin signals a shift. Rather than reacting to changes, an optimised system allows you to instantly apply new rules, such as the new day-one SSP rights (effective April 2026), ensuring you remain compliant with worker entitlements as soon as they become law.

Integrate and audit for total control 

Payroll automation eliminates duplicate data entry and manual errors across HR and accounting systems. This one shared, up-to-date record allows you to perform internal audits and reconcile reports with bank payments effortlessly. Finally, ensure your team is trained to maintain the mandatory record retention trail, 3 years for PAYE records and 6 years for holiday pay records under the Employment Rights Act 2025, keeping your business audit-ready at all times.