Payroll mistakes small business owners make are usually not dramatic fraud issues or complex technical failures. More often, they come from simple reporting errors such as using the wrong payment date, submitting the wrong employee details, choosing the wrong National Insurance category letter or missing a discrepancy between payroll records and HMRC’s view of the PAYE bill.
The good news is that most payroll problems can be reduced with better checks, cleaner employee data and a clear correction process. HMRC’s own guidance highlights a number of repeat problem areas and explains what employers should review when a PAYE bill looks wrong, including whether the Full Payment Submission (FPS) or Employer Payment Summary (EPS) was sent on time and whether the employer used the employee payment date rather than the submission date. You can see that in HMRC’s guidance on fixing problems with running payroll.
In this guide, Business Help Group UK explains the most common payroll mistakes, why they happen and how UK businesses can avoid them. If you run payroll for a limited company, family business, growing employer team or owner-managed business, these are the controls worth putting in place now.
Why payroll mistakes matter more than many small businesses realise
Payroll is not just an internal admin task. It affects staff pay, tax deductions, National Insurance reporting and your ongoing PAYE position with HMRC. A small input error can create a chain reaction:
- employees may be paid the wrong amount
- deductions can be reported incorrectly
- HMRC’s PAYE bill can look higher or lower than expected
- records may need to be amended in later submissions
- management time gets pulled into firefighting rather than running the business
For small businesses especially, payroll errors can be expensive in time alone. They also damage trust with employees if wage slips or payment timing become unreliable.
That is why a prevention-first approach matters. Clean data, consistent processes and regular reconciliations usually solve more problems than trying to fix everything after HMRC raises a query.
Common payroll mistakes small business owners make
HMRC’s guidance on correcting payroll submissions identifies several common mistakes employers make in FPS or EPS reporting. These include wrong pay or deductions, wrong payment dates, wrong start or leaving dates, wrong employee information, wrong NI category letters and incorrect EPS entries. The official correction guidance is here: Correct payroll errors in your FPS or EPS.
Below are the errors we see most often in practice.
1. Using the wrong payment date
This is one of the most common causes of payroll confusion. HMRC specifically says that if a PAYE bill looks wrong, employers should check whether they used the employee payment date rather than the submission date. That distinction matters because the payroll submission should reflect when the employee was actually paid, not simply the date the file was sent. HMRC states this in its guidance on fixing payroll problems.
How to avoid it:
- agree one clear payroll payment date for each payroll cycle
- make sure the date in payroll software matches the actual employee payment date
- do a final date check before sending the FPS
- avoid rushing submissions at the last minute without a second review
2. Reporting wrong pay or deductions
Simple data-entry mistakes still cause a large share of payroll errors. If gross pay, deductions or adjustments are entered incorrectly, that error can flow into payslips, bookkeeping records and PAYE reporting.
How to avoid it:
- use a payroll checklist before each run
- reconcile pay changes to approved records such as salary change confirmations or timesheets
- have someone review unusual variances before final submission
- keep a month-by-month payroll summary so unexpected movements stand out quickly
For very small teams, even a basic comparison against the previous pay run can catch many avoidable errors.
3. Getting employee details wrong
HMRC lists wrong employee information as a common reporting mistake. That can mean a mismatch in identifying details or incomplete starter information. Even when the pay itself is correct, poor employee data can create processing issues and confusion later.
How to avoid it:
- collect employee information through one standard onboarding process
- check records are complete before the first payroll run
- update name or address changes promptly in the payroll system where relevant
- avoid duplicate manual records kept in different spreadsheets
In practical terms, the more places employee data is retyped, the more likely mistakes become.
4. Entering the wrong start date or leaving date
Wrong start and leaving dates are another issue HMRC specifically flags in its correction guidance. These dates affect how employment records are presented to HMRC and can contribute to wider payroll discrepancies if they are inconsistent with the payroll history. See HMRC’s official page on correcting FPS or EPS errors.
How to avoid it:
- confirm the agreed employment start date from signed onboarding records
- record leavers as part of a formal offboarding process rather than by email alone
- review payroll status changes before each pay run
- keep HR and payroll records aligned
5. Using the wrong NI category letter
HMRC also identifies wrong NI category letters as a common payroll reporting mistake. This is an area where assumptions can be risky. If the category letter is wrong, the payroll position may be wrong as well and the mistake may continue until somebody spots it.
How to avoid it:
- do not guess a category letter when setting up an employee
- make sure the setup is reviewed by someone experienced in payroll
- check that payroll software settings match the employee’s circumstances and current records
- review exceptions and unusual categories separately
Where there is uncertainty, it is better to pause and review the position properly than process payroll on an unchecked assumption.
6. Incorrect EPS entries
HMRC’s correction guidance also refers to incorrect EPS entries. If the EPS is wrong, HMRC’s view of what is due can be wrong too. That is one reason employers should compare their own records with HMRC’s position regularly rather than waiting for a larger discrepancy to appear.
How to avoid it:
- know when your business needs to send an EPS and why
- review the EPS separately from the FPS rather than treating it as an afterthought
- keep supporting notes for entries so they can be explained later if needed
- reconcile submissions to the payroll control account and PAYE records
7. Creating duplicate employee records
HMRC has published guidance explaining that duplicate employee records can happen when an employee starts a new employment. HMRC also says employers should tell it about discrepancies whether they create a debit or a credit. That point is set out in HMRC’s support material on preventing payroll errors and disputed PAYE charges: Help to prevent payroll errors and PAYE RTI disputed charges.
How to avoid it:
- check carefully before creating a new employee file for someone already known to the business
- review employee lists for similar names or duplicate identifiers
- keep a clear audit trail when an individual has a genuine new employment
- investigate PAYE discrepancies early rather than assuming they will self-correct
What to do if your HMRC PAYE bill looks wrong
If HMRC’s PAYE bill does not match your expectations, do not ignore it and do not assume it will disappear next month. HMRC says employers should check whether FPS or EPS submissions were sent on time and whether the employee payment date was used correctly. That is the starting point in HMRC’s official guidance on fixing problems with running payroll.
A practical review process often looks like this:
- compare HMRC’s figure with your payroll records for the relevant period
- check the payment date used in the payroll submission
- review whether any FPS or EPS was missed, sent late or sent with incorrect data
- look for duplicate employee records or duplicated submissions
- check starter, leaver and employee details for inconsistencies
- identify whether the discrepancy creates an underpayment or overstatement
HMRC also provides a dedicated support route to help employers dispute an employer PAYE charge and find or correct a payroll mistake. The official guidance is here: Get help to correct an employer PAYE bill.
That service is useful where your records and HMRC’s position do not align and you need a structured route to investigate the issue.
How to build a payroll process that prevents repeat errors
The best payroll system for a small business is not necessarily the most complex one. It is the one with the fewest points of failure. Good payroll control usually comes down to disciplined habits.
Create a repeatable monthly checklist
Use a standard pre-payroll checklist covering starters, leavers, pay changes, leave impacts, one-off payments and review points for FPS and EPS data. A checklist reduces reliance on memory and helps continuity if more than one person touches payroll.
Separate preparation from final review
Even in a small business, try to have one person prepare the payroll and another review key points before submission. If that is not possible internally, an external payroll provider or accountant can provide a valuable second set of eyes.
Keep onboarding and payroll connected
Many payroll issues start before the first payslip is ever produced. If HR, admin and payroll each hold different versions of employee information, errors are almost inevitable. A single source of approved employee data is far safer.
Reconcile every period
Do not wait until year end to discover a mismatch. Reconcile payroll records regularly against bookkeeping and against what HMRC says is due. Early correction is usually easier than untangling several months of errors.
Escalate unusual cases early
If an employee situation looks out of the ordinary, treat it as a review point rather than a routine setup. That is particularly important where software defaults may not reflect the employee’s actual circumstances.
Should you keep payroll in-house or outsource it?
For some businesses, running payroll in-house works perfectly well if there is a reliable process and someone competent overseeing it. For others, outsourcing reduces risk and frees up management time.
You may want support if:
- payroll errors keep recurring
- HMRC’s PAYE bill does not reconcile cleanly
- you have limited internal capacity
- different people are updating payroll data without clear control
- you are hiring more staff and complexity is increasing
Outsourcing does not remove your responsibilities as an employer, but it can improve accuracy, reporting discipline and record keeping when handled properly.
FAQ: common payroll questions from small businesses
What are the most common payroll mistakes in a small business?
HMRC highlights common payroll-reporting mistakes including wrong pay or deductions, wrong payment dates, wrong start or leaving dates, wrong employee information, wrong NI category letters and incorrect EPS entries. HMRC’s correction guidance is here: Correct payroll errors in your FPS or EPS.
Why does HMRC show the wrong PAYE bill?
According to HMRC, one reason may be that the FPS or EPS was not sent in time or that the wrong date was used in the submission. HMRC says employers should check whether they used the employee payment date rather than the submission date. See Fix problems with running payroll.
Can duplicate employee records cause payroll problems?
Yes. HMRC says duplicate employee records can happen when an employee starts a new employment. Employers should also tell HMRC about discrepancies whether they create a debit or a credit. The official guidance is here: Help to prevent payroll errors and PAYE RTI disputed charges.
What should I do if I cannot resolve a PAYE discrepancy?
HMRC has a dedicated service to help employers dispute an employer PAYE charge and identify or correct a payroll mistake. You can review that route here: Get help to correct an employer PAYE bill.
Final thoughts
Most payroll mistakes small business owners face are preventable. The pattern is usually the same: inaccurate employee data, rushed processing, weak review steps or a mismatch between what happened in reality and what was reported to HMRC.
If you tighten your payroll workflow, review submissions before they go and reconcile regularly, you can reduce the chance of staff pay issues and HMRC disputes significantly. And if something already looks wrong, acting early is almost always better than hoping the issue resolves itself later.
Business Help Group UK supports businesses that want payroll handled properly, with fewer errors and clearer reporting. If you need help reviewing your payroll process, correcting recurring PAYE issues or deciding whether to outsource payroll, get in touch with Business Help Group UK to discuss practical support tailored to your business.
