How payroll works for small businesses is one of those questions that sounds straightforward until you’re actually doing it at 10pm on a Thursday, wondering if you’ve filed the right thing to HMRC.

What Payroll Actually Involves

At its core, payroll is the process of calculating how much each employee is owed, deducting income tax and National Insurance contributions, and paying the right amounts to both your staff and HMRC. It sounds simple. In practice, it involves a lot of moving parts.

The part that catches a lot of employers off guard is something called Real-Time Information, or RTI. HMRC requires you to report payroll information electronically before you actually pay your employees, not after. That means a Full Payment Submission has to go to HMRC on or before every payday, every time. Miss it, and you’re looking at a potential fine.

The Rules You Need to Keep Up With in 2026

Payroll rules change every year, and 2026 has brought a few things that are worth knowing about. New National Minimum Wage rates apply from April 2026, and HMRC’s April 2026 Employer Bulletin also confirms that Benefits in Kind, things like private medical cover or company cars, now need to be registered for payrolling by 5 April 2026 if you want them processed through the payroll system for the 2026-27 tax year. If you missed that deadline, you will need to sort it through your P11D instead.

Auto-enrolment pension contributions are also part of the picture for any employer with eligible staff. You need to assess your workforce, enrol the right people, make the correct contributions, and keep records to show you have done it. It is one of those compliance areas that is easy to get wrong quietly, and then suddenly very visible when something goes wrong.

Where Small Businesses Tend to Go Wrong

The numbers are pretty uncomfortable. Research into UK SME payroll practices shows that around 84% of small businesses admit to making payroll errors, with nearly half of those involving wrong wage calculations. And 40% of small businesses have paid fines because of payroll problems, whether that is underpaying staff or filing issues with HMRC. That is not a small number.

A lot of this comes down to doing it manually, often on spreadsheets, trying to keep up with changing rates and rules at the same time as running a business. There is no shame in that. I did it myself for years before I qualified as an accountant. But the honest truth is that the rules are detailed enough, and the penalties real enough, that manual payroll is a genuine risk for most small employers.

When Does It Make Sense to Get Some Help?

If payroll is taking you more than an hour a month, if you are not confident your RTI submissions are going in correctly, or if you have had any changes to staff numbers, wages or benefits recently, it is probably worth talking to someone. The cost of a payroll service is almost always less than the time and stress of doing it yourself, and far less than the cost of getting it wrong.

What puts a lot of people off is the fear of it being complicated to hand over. In my experience, it rarely is. I need a few details, access to your payroll records, and a clear picture of who you are paying and how. From there, I take care of the calculations, the payslips, the RTI submissions and the pension reporting. You approve the numbers, and the rest is handled.