A complete guide to outsourcing payroll

Payroll outsourcing, sometimes called managed payroll, is when a business uses an external provider to run payroll on its behalf.

Depending on the service, this can include calculating pay, managing deductions, producing payslips, processing payments and submitting payroll information. Some businesses outsource the entire process, while others keep certain tasks in-house.

Although day-to-day payroll tasks can be handled by an external provider, the employer remains legally responsible for payroll compliance. For this reason, it’s important to choose a reliable and reputable managed payroll service that can support you in meeting your obligations. 

Exactly how your payroll service works will depend on the service you choose.  

Typically, each pay period the employer provides the payroll provider with up-to-date employee information. This includes hours worked, pay changes, bonuses, statutory leave, or details of new starters and leavers.

Payroll data is usually shared through secure systems, such as payroll software or a dedicated portal provided by the payroll partner. Once the data is received, the provider completes the agreed payroll tasks such as calculating pay and deductions, producing payslips, and preparing payments and payroll reports.

Before payroll is finalised, employers can review and approve the figures. Once approved, payments are processed and payroll records are updated. 

Payroll services aren’t one-size-fits-all. There are several different forms that a payroll service can take. Consider which of the following might best fits your needs:

Fully managed payroll

Fully managed payroll is the most comprehensive form of payroll outsourcing. The provider takes responsibility for running most of your payroll activities, working closely with your business as an external payroll team.

This option is often chosen by businesses with larger or more complex payrolls, or those that want to reduce internal workload while maintaining oversight and approval. It can also suit organisations without dedicated payroll expertise in-house.

General payroll admin

General payroll admin services provide support with specific payroll tasks, while the business retains control over the wider process.

This may include activities such as processing BACS payments, producing payslips or supporting payroll reporting. It’s a good fit for businesses that already run payroll internally but want to reduce admin or improve efficiency without fully outsourcing.

Transactional payroll

Transactional payroll is designed for businesses with small or infrequent payroll requirements. This could include organisations with a limited number of employees, irregular payroll cycles, or specific one-off payroll needs.

It’s commonly used by smaller businesses but can also support larger organisations in specific cases, such as paying a small group of employees or handling a standalone payroll requirement.

Short-term payroll

Short-term payroll, sometimes referred to as emergency payroll, provides temporary support when a business is unable to run payroll internally.

This can be useful during periods of transition, staff absence, system changes or unexpected disruption. Short-term payroll services help ensure employees continue to be paid accurately and on time while longer‑term arrangements are put in place. 

Businesses choose to outsource payroll for lots of reasons. As payroll becomes more complex, managing it in-house can take up significant time and increase the risk of errors.

Common reasons businesses choose to outsource their payroll include:  

Improving accuracy and reliability

Specialist providers use dedicated payroll systems and experienced payroll professionals to reduce the risk of mistakes.

Supporting compliance

Payroll providers stay up to date with legislative changes and help ensure payroll processes follow current requirements.

Reducing administrative workload

Outsourcing payroll frees up HR and finance teams from day‑to‑day processing, allowing them to focus on more strategic work.

Cost efficiency

For many businesses, outsourcing can be more cost‑effective than maintaining in‑house payroll expertise, particularly when training, systems and error‑related costs are considered. 

To learn more, read our guide: 10 Reasons to Outsource Your Payroll

Businesses of all sizes outsource payroll, but it’s most common when pay has become too time‑consuming, complex or difficult to manage alongside other responsibilities.

Employers often choose to outsource payroll when:

• The number of employees is growing
• Payroll rules and legislation are becoming harder to keep up with
• Payroll responsibilities sit alongside wider HR or finance roles
• Errors or delays have started to create risk or employee dissatisfaction

Should small businesses outsource payroll?  

Managed payroll services are often associated with larger organisations with complex workforces, but many small and medium-sized businesses outsource their payroll too. There are three key reasons for this:

Managing payroll is a time-consuming task, and small businesses often lack the capacity to give it the attention it requires. Payroll responsibilities are frequently added to an HR or finance role, which can distract from other important priorities.

As small businesses grow, payroll quickly becomes more complex. Without a dedicated payroll function, businesses can run into growing pains when headcount increases, pay structures change or new compliance requirements apply.

Small businesses are particularly vulnerable to payroll errors that can lead to fines or penalties. Keeping up with ever-changing payroll legislation is challenging alongside the day-to-day demands of running a business, making expert support especially valuable.

Real-world examples

MHR provides managed payroll services for organisations with a wide range of needs, from growing businesses to large employers with complex payroll requirements.

For example Severn Trent needed a reliable and efficient service to accurately manage payroll for their workforce of over 7,000 employees.  

On their decision to continue to use MHR’s managed payroll service, Joe Carter, HR Manager at Severn Trent said: “their outsourcing team has been invaluable to ensuring our payroll process is not only delivered successfully but continually evolves to support our growth and strategic goals.” 

Before deciding to outsource, it’s important to think about how the service will work for your business in practice. Taking time to assess your needs upfront can help you choose the right level of support.

Key factors to consider include:

The size and complexity of your payroll

The number of employees you have, how often you run payroll, and how complex your pay structures are will all influence the type of service you need. Businesses with multiple payrolls, variable pay or frequent changes may benefit from a more fully managed approach.

Internal resources and expertise

Consider how much payroll knowledge and capacity you have in‑house. If payroll is managed alongside other HR or finance responsibilities, outsourcing can help reduce pressure and reliance on key individuals.

Data security and GDPR

Payroll involves sensitive personal and financial data. It’s important to understand how your provider handles data, including how information is shared, stored and protected, and how they support compliance with data protection requirements.  

Service levels and ongoing support

Look at what support is available day to day. This includes response times, access to payroll specialists, and how issues or urgent changes are handled during the pay cycle.

Integration with existing systems

Payroll often relies on data from HR, finance or time and attendance systems. A service that integrates smoothly with your existing setup can reduce manual work and the risk of errors.

Your long‑term business goals

Payroll outsourcing should support where your business is heading, not just where it is today. Think about future growth, organisational change or increasing compliance requirements, and whether the service can scale with you.

Payroll software versus outsourcing

In some cases, investing in payroll software may be enough. In others, combining software with outsourced payroll expertise provides additional reassurance and support. Understanding the difference can help you make a more informed decision. 

Choosing the right payroll provider is just as important as deciding to outsource in the first place. Payroll is a critical business function, so it’s important to work with a partner that offers the right balance of expertise, reliability and support.

When assessing payroll providers look for:

• Proven experience supporting payroll for organisations of a similar size or complexity
• Clear processes and service levels, including support during payroll runs
• Strong data security and compliance practices
• Qualified payroll professionals with up‑to‑date legislative knowledge

MHR supports organisations across a wide range of industries, providing managed payroll services tailored to different business needs. With over 40 years’ experience, MHR’s payroll services are delivered by CIPP and IPASS‑accredited payroll professionals, giving employers confidence that payroll is handled by trained specialists who understand both the technical and regulatory aspects of payroll.

Whether you’re looking to fully outsource payroll or need support with specific parts of the process, MHR works with you to provide a reliable, secure and scalable payroll solution.