Payroll Mistakes That Could Cost Your Business Thousands

When payroll is running smoothly, employees get paid, HMRC receives the correct submissions, and business owners can focus on running their company. But when payroll goes wrong, things can get expensive very quickly.

As accountants, we regularly see businesses making the same payroll mistakes.

The good news is that most payroll problems are completely avoidable.

Here are some of the most common payroll mistakes we see that could end up costing your business money.

Missing Payroll Deadlines

HMRC isn't known for its relaxed attitude towards deadlines.

If you're running payroll, you need to submit your Full Payment Submission (FPS) on or before the day your employees are due to be paid. Missing this deadline can result in penalties, particularly for businesses that repeatedly file late.

Late payment of PAYE and National Insurance can also lead to interest charges and additional penalties.

How to avoid it

• Set up payroll calendars with key submission dates.

• Use payroll software with deadline reminders.

• Consider outsourcing payroll to help ease the workload.

Getting Employment Status Wrong

Just because someone sends you an invoice doesn't automatically make them self-employed.

Many businesses incorrectly treat individuals as self-employed when, under HMRC rules, they should be on the payroll. If HMRC later decides they should have been treated as an employee, the business could find itself responsible for unpaid tax, National Insurance, plus penalties and interest. That's not a letter anyone enjoys opening.

This risk is particularly relevant in industries such as construction, IT, consultancy, logistics, and professional services.

How to avoid it

• Review employment status before engaging individuals.

• Use written contracts that reflect the actual working relationship.

• Seek professional advice if you're unsure.

Auto-Enrolment Pension Mistakes

Workplace pensions have been around for years now, but businesses still get caught out.

Common mistakes include:

• Not enrolling eligible employees.

• Using the wrong contribution rates

• Missing pension submission deadlines.

• Assuming "the software probably sorted it."

The Pensions Regulator can impose fines for non-compliance, and these can escalate if issues are not resolved promptly.

How to avoid it

Review pension reports regularly and don't assume everything is running perfectly in the background!

Accidentally Paying Below Minimum Wage

This catches out more employers than you'd think, and it's not always because someone intentionally underpays staff.

Sometimes deductions for uniforms, salary sacrifice arrangements, or unpaid training time can push pay below the legal minimum.

HMRC actively checks for this, and businesses found to be in breach can face penalties and unwanted publicity. Nobody wants their company appearing in a newspaper article for the wrong reasons.

How to avoid it

• Review pay calculations regularly.

• Pay particular attention to lower-paid workers.

• Conduct annual minimum wage checks.

Incorrect Holiday Pay Calculations

Holiday pay can get surprisingly complicated, particularly for employees with irregular hours, overtime, commission, or variable earnings.

Incorrect calculations can lead to:

• Employee grievances.

• Employment tribunal claims.

• Backdated payment liabilities.

How to avoid it

• Ensure payroll software reflects current holiday pay rules.

• Review calculations for employees with overtime, commissions, or variable earnings.

• Keep accurate records of working hours and leave taken.

Not Applying Tax Code Changes

HMRC regularly issues tax code notices throughout the year, and payroll software doesn't always magically update itself.

Failing to update employee tax codes can result in incorrect PAYE deductions, leading to employee complaints and additional admin.

How to avoid it

• Monitor HMRC notifications regularly.

• Ensure payroll software imports tax code changes automatically where possible.

• Apply employee tax codes promptly.

Getting Statutory Pay Wrong

Sick pay, maternity pay, paternity pay, and other statutory payments all come with their own rules. The calculations aren't impossible, but they're not something you want to guess your way through either.

How to avoid it

• Maintain clear employee absence records.

• Record when statutory pay is paid.

• Seek advice for complex cases.

Never Checking the Numbers

Payroll software is brilliant. We use it every day. But software is only as good as the information entered into it.

If nobody reviews payroll reports, mistakes can go unnoticed for months. Duplicate payments, missing employees, and incorrect deductions can all slip through because nobody checks the final figures.

How to avoid it

• Reconcile payroll reports each month.

• Compare payroll liabilities with HMRC account balances.

• Review unusual fluctuations in payroll costs.

Trying to Manage Payroll Without Professional Support

This is probably the biggest mistake of all.

Payroll can look straightforward from the outside. After all, you're just paying people, right?

Then along comes pension legislation, minimum wage compliance, statutory pay rules, tax code changes, employment status questions, and HMRC deadlines.

Suddenly, it's not quite as simple as it seemed.

How to avoid it

If payroll is taking up too much time or causing stress every month, consider getting professional support.

A good accountant can be considerably cheaper than fixing mistakes after they've happened.

Final Thoughts

Payroll is one of those business tasks that's easy to ignore when everything is working properly. But when mistakes happen, they can be expensive, time-consuming, and frustrating for everyone involved.

The best approach is to be proactive. Review your payroll processes regularly, keep accurate records, and don't be afraid to ask for help when something doesn't look right.

Because while HMRC may forgive the occasional honest mistake, they generally prefer businesses to get things right the first time.

And if there's one thing every business owner can agree on, it's that nobody wants surprise letters from HMRC arriving with their morning post.