The Pre-Payslip Checklist: Verify Every Deduction Before Payday

Most people glance at their payslip, see a number deposited, and move on. But payroll errors are more common than HR departments would like to admit — wrong tax codes, missed reimbursements, duplicate deductions, benefits charged at the wrong rate. The cumulative damage over a year can run into hundreds of pounds or dollars without anyone flagging it.

This checklist is designed to be run before you accept the month's pay as gospel. Treat it the way a pilot treats a pre-flight check — methodical, unhurried, and done every single time. You don't need an accountancy background. You need the checklist and about twenty minutes.

Step 1: Pull Together Your Source Documents

Before you can verify anything, you need the raw material. Don't skip this step — checking a payslip against memory is how errors survive.

This month's payslip — digital or paper, make sure it's the final version, not a draft.
Last month's payslip — your baseline for spotting anything that changed unexpectedly.
Your employment contract or offer letter — for your gross salary, agreed allowances, and any guaranteed bonuses.
Your current tax code notice (in the UK, a P2 or equivalent letter from HMRC; in the US, your W-4 on file with payroll).
Any benefit enrollment confirmation emails — health insurance, pension/401(k) contribution rate, salary sacrifice agreements.
Expense reimbursement submissions — anything you submitted that should appear as a non-taxable reimbursement this cycle.

Step 2: Confirm Your Gross Pay Is Correct

Everything else flows from this number, so if gross is wrong, every deduction percentage calculated on top of it will also be wrong.

Base salary matches your contract. Divide your annual salary by 12 (or by 52 and multiply by your pay frequency). Does the figure on the payslip match?
Any pay rise effective this month has been applied. If you received a raise starting this month, check the new rate — not the old one — is reflected.
Overtime, commission, or variable pay is included if earned. Cross-reference against your own records or the commission statement your manager approved.
Any one-off bonus agreed in writing appears at the correct gross amount.
If you worked fewer days due to joining or leaving mid-month, the prorated calculation is accurate. The formula is: (Annual Salary ÷ Working Days in Year) × Days Worked This Month.

Step 3: Check Your Tax Code or Withholding Status

This is where a surprising number of quiet errors live. A wrong tax code can either drain your pay unnecessarily or leave you with a large bill at year-end — neither is good.

Your tax code (UK) or filing status (US/CA) on the payslip matches what you've confirmed with the tax authority. In the UK, if you see an emergency code like 1257L W1 or 1257L M1, you're being taxed on a week/month-by-month basis — that needs fixing with HMRC.
You haven't been put on a BR (basic rate) code by mistake. This happens when payroll can't verify your other income and defaults to taxing everything at 20% with no personal allowance applied.
If you updated your W-4 or equivalent this year, payroll has the new version on file. Ring or email payroll to confirm — they should be able to tell you what withholding elections they're using.
Tax withheld this month is consistent with last month's, adjusted only for any change in gross pay. A sudden spike in income tax with no corresponding pay rise is a red flag.

Step 4: Scrutinise National Insurance, Social Security, or Equivalent Contributions

NI category letter (UK) is correct. Most employees are Category A. If you're over state pension age, you should be Category C (no NI deducted). Wrong category = wrong rate.
The NI or Social Security amount is within expected range. In the UK in 2024–25, the employee NI rate on earnings between £12,570 and £50,270 is 8%. A back-of-envelope check: (Monthly Gross − £1,047) × 8% ≈ your NI. Wildly different? Investigate.
If you have more than one job, NI is not being double-deducted on amounts below the threshold.

Step 5: Pension / Retirement Contribution Verification

Pension deductions are one of the most error-prone line items — partly because contribution rates change, partly because salary sacrifice arrangements can be set up incorrectly at the start and never reviewed.

Your employee contribution percentage matches what you elected. If you opted to contribute 5% and the payslip shows 3%, you're underfunding your pension and potentially receiving less employer match.
The employer contribution is showing on your payslip or pension portal at the correct rate. This isn't a deduction from you, but it should match what's written in your contract or the auto-enrolment confirmation.
If contributions are salary sacrifice, the pre-sacrifice gross and post-sacrifice gross are both shown correctly. Your NI should be calculated on the lower (post-sacrifice) amount — that's the point of the arrangement.
After any salary change, the pension deduction has updated proportionally. Payroll systems sometimes retain a fixed monetary amount rather than recalculating the percentage.

Step 6: Benefits and Voluntary Deductions

Health/dental/vision insurance premium matches your enrollment confirmation. Mid-year plan changes often glitch — the new premium sometimes takes an extra cycle to update.
Any salary sacrifice for cycle-to-work, electric vehicle, or childcare vouchers reflects only what you actually enrolled for.
If you cancelled a benefit, the deduction is no longer present. Cancelled gym memberships, lapsed dental riders, and dropped optical cover have a habit of lingering in payroll like uninvited houseguests.
Union dues, professional subscriptions, or voluntary savings plans are at the current agreed rate.
Any court-ordered deductions (attachment of earnings, garnishment) are exactly as specified in the legal order — not more, not less.

Step 7: Reimbursements and Non-Taxable Additions

This section is about money that should be coming back to you — and often quietly isn't.

Approved expense claims submitted before payroll cut-off appear as a non-taxable reimbursement line item.
Any mileage allowance is calculated at the approved rate (in the UK, 45p/mile for the first 10,000 miles).
If a reimbursement has been processed as taxable income by mistake, it's inflating your gross and costing you tax you shouldn't owe. Flag this immediately — it needs a corrected payslip, not just a note.
Any working-from-home allowance or tool stipend is present if it was approved for this period.

Step 8: Year-to-Date Totals and Running Sense Checks

These are your audit trail. If your payslip shows cumulative year-to-date figures, they're more revealing than any single month's numbers.

YTD gross earnings ÷ number of months paid so far = this month's gross (if pay has been consistent). A discrepancy here often surfaces a month where something was missed or double-counted.
YTD tax paid is tracking at the right proportion of YTD gross, given your tax code. If you're three months into the year and have already paid what looks like six months' worth of tax, investigate.
Your net pay (take-home) is within a reasonable range of last month's. A swing of more than 5–8% with no known reason — no pay rise, no new benefit, no changed hours — deserves a call to payroll.

What to Do When You Spot an Error

Finding a discrepancy doesn't mean payroll is being dishonest — most errors are system glitches or missed updates, not malice. But the correction process matters.

Document first. Screenshot or save the payslip before anything changes. Note the specific line item, the amount shown, and what it should be.
Email payroll — don't just call. You want a paper trail. State the error clearly, cite the source document that supports your position (contract clause, benefit enrollment confirmation, HMRC notice).
Ask for a corrected payslip and confirmation of when the adjustment will be processed. Most payroll teams will either correct it next month or run an off-cycle payment for significant amounts.
If tax was over-withheld and it's a tax code error, contact HMRC directly (or the IRS if you're in the US) in addition to informing payroll — the correction at the payroll level may not automatically trigger a refund without the code being updated.
Follow up in writing if you don't hear back within five working days.

Running this checklist once takes time. Running it every month takes about fifteen minutes once you know what you're looking for. The effort compounds — over a career, catching even one significant error per year is easily worth it. Your payslip is a legal document that affects your tax record, your mortgage applications, and your pension pot. It's worth reading like one.