Guide
Payroll Mistake Checklist: What to Check First
When a payslip looks wrong, the fastest fix usually starts with a clean evidence pack rather than an accusation.
Quick answer
Separate the issue into gross pay, taxable pay, PAYE tax, National Insurance, student loan, pension, and net pay. Then compare each line with the tax code, pay period, and year-to-date totals before contacting payroll, HMRC, SLC, or the pension provider.
Start with the payslip facts
Before you contact payroll, copy the facts from the payslip exactly as shown. Do not start with the net-pay difference alone. Payroll needs to know which input or deduction line you think is wrong.
| Field | Why it matters |
|---|---|
| Pay period and pay date | PAYE and NI are calculated for a specific period, not just the month you noticed the problem. |
| Gross pay | This should match salary, overtime, bonus, commission, statutory pay, or hourly records. |
| Taxable pay | This can be lower than gross pay if pension or salary sacrifice is taken before tax. |
| NI-able pay | This can differ from taxable pay because NI has different rules from income tax. |
| Tax code and basis | BR, 0T, 1257L, K codes, W1, M1, or X can all change the PAYE result. |
| Year-to-date totals | Cumulative PAYE uses the tax-year history, so one payslip can only be checked properly with YTD figures. |
Check the numbers before escalating
A short calculation check helps you separate a payroll arithmetic issue from an HMRC, student-loan, or pension-record issue.
Separate the problem buckets
A messy payslip often contains more than one problem. Treat each one separately so the right organisation can fix the right part.
- Gross pay or hours: check your contract, rota, timesheet, overtime approval, commission statement, or bonus letter.
- PAYE tax: check the tax code, W1/M1 basis, taxable pay, and HMRC Personal Tax Account.
- National Insurance: check NI category and pay-period earnings. NI is not reconciled across the year like PAYE.
- Student loan: check the plan type, postgraduate loan flag, pay-period threshold, and whether payroll has received a start or stop notice.
- Pension: check whether the scheme is salary sacrifice, net pay, or relief at source, then compare payslip deductions with the pension provider statement.
- Unpaid wages or missing remittance: keep this separate from a tax calculation error. Deductions taken but not paid onward may need a different escalation route.
What to send payroll
Keep the first message short and factual. A clear written record is more useful than a long explanation of everything that feels wrong.
Suggested format:
- Pay period and pay date.
- The line that looks wrong.
- The figure shown on the payslip.
- The figure you expected and why.
- Evidence attached: payslip, contract, timesheet, P45, HMRC tax-code notice, student-loan notice, or pension statement.
- The correction you are asking payroll to check.
Use neutral wording such as "please explain how this was calculated" or "please confirm whether this line should be corrected". Save stronger language for later if the evidence supports it.
Who to contact after payroll
If payroll cannot fix the issue, the next contact depends on the bucket.
| Issue | Likely next contact |
|---|---|
| Wrong tax code or old employment still showing | HMRC Personal Tax Account or income tax helpline |
| Student loan taken when records look wrong | Student Loans Company after payroll confirms the plan/notice used |
| Pension deducted but not visible in pension account | Pension provider first, then The Pensions Regulator if needed |
| Unpaid wages, wrong hourly rate, or contract dispute | Payroll/HR in writing, then ACAS guidance if unresolved |
| PAYE calculation does not match the code and taxable pay | Payroll first; HMRC if payroll says it is following an HMRC code |
Do not share full payslips publicly. Redact your National Insurance number, payroll number, address, employer details, bank details, and any other personal identifiers.
What to check
- Record the exact tax code, pay period, NI category, student loan plan, and pension method shown or implied by the payslip.
- Separate calculation problems from missing payments, unpaid wages, or pension contributions that may not have reached the provider.
- Keep the language factual: ask payroll to explain or correct the line, rather than calling it fraud before the evidence is clear.
What to do next
- Run the payslip checker with the exact payslip numbers.
- Send payroll a short written summary with the period, line item, expected figure, observed figure, and evidence attached.
- Escalate the right part of the issue only after payroll has responded: HMRC for tax-code records, SLC for loan records, the pension provider for pension receipts, or ACAS for wage disputes.
Try the tool
Check your payslip or model a change.
Use the checker if you already have a payslip. Use the calculator if you want to model take-home pay or salary-sacrifice changes before payday.
About this guide
Published by IsMyPayRight to help you understand pay and deductions. Guides use official reference material and practical examples, with AI assistance in content preparation.
This is general guidance, not a professional review of your circumstances. Read our editorial process and corrections information.
Methodology and sources
See how the calculations work, which sources they use, how results are tested, and which payroll details the estimates cannot verify.
Common questions
- What should I check before telling payroll my payslip is wrong?
- Record the pay period, gross pay, taxable pay, NI-able pay, tax code, NI category, pension line, student-loan plan, net pay, and year-to-date totals. Payroll can usually investigate faster when you point to a specific line.
- Should I contact payroll, HMRC, SLC, or my pension provider?
- Start with payroll for payslip calculation or gross-pay issues. Contact HMRC for tax-code records, SLC for student-loan records, and the pension provider if deductions were taken but do not appear in your pension account.
- Should I call a payroll error fraud?
- Not at first. Keep the first message factual and ask for the calculation or remittance to be explained. Escalate only when you have evidence of the specific issue and the right route for that issue.
Official sources
Official sources
Use these references to check the rules behind this guide. Check the tax year and your circumstances before applying an example to your own pay.