Payslip Decoder (UK)
Updated November 2026 · Free · No sign-up
Decode your UK payslip line by line — PAYE against your tax code, National Insurance at the 8%/2% bands, pension, student loan plans — and a quick net-pay sanity check against what landed in the bank.
Quick answer: A UK payslip’s big five: PAYE tax (your tax code ÷ 12 of allowance, then 20/40/45%), NI (8% between ~£1,048-£4,189/month, 2% above), pension (usually 5% of band earnings), student loan (9% above the plan threshold), and the YTD columns that catch cumulative errors.
Reading the Lines
| Line | What it should be | Red flags |
|---|---|---|
| Tax code | 1257L standard (£12,570 allowance ÷ 12 = £1,047.50/month tax-free) | BR/0T/W1/M1 = emergency or no allowance — fix it; K codes = owed benefits tax |
| PAYE | 20% to ~£4,189/month taxable, 40% beyond, 45% top (cumulative basis) | Sudden jumps without a pay change |
| NI (letter A usually) | 8% between the primary threshold and UEL, 2% above | Wrong letter (C for pension-age, H/M apprentice/young) |
| Pension | Your % — check RELIEF basis (net-pay vs RAS) matches the scheme | Missing employer line, relief applied twice/never |
| Student loan | 9% above YOUR plan’s monthly threshold | Wrong plan (overseas movers), deductions after clearing |
| YTD columns | Cumulative gross/tax/NI — the error-catchers | YTD ≠ sum of payslips → payroll restated something |
The Classic Errors
Emergency codes after job changes (overpaying £100s/month, refundable), duplicate NI on two jobs (claim category adjustments), pension relief mismatches, and missed OT-inclusive holiday pay. The estimator below approximates a standard code — differences over ~£20 from your actual slip deserve a question to payroll.
Your Rights
Itemized payslips are a day-one legal right (including hours for variable-pay staff); unexplained deductions are unlawful without written authority. Keep slips 22+ months minimum (HMRC’s P60 cycle); your Personal Tax Account at gov.uk shows what HMRC thinks — mismatches with payroll are where refunds hide. Figures here use 2025/26-era bands; verify current thresholds.
Frequently Asked Questions
What should my tax code be?
1257L for a standard single-job allowance — BR, 0T, W1/M1 emergency codes and unexplained K codes are the overpayment flags worth a call to HMRC.
How is NI calculated?
Employee Class 1: 8% of monthly earnings between roughly £1,048 and £4,189, 2% above — per job, non-cumulative (unlike PAYE).
Why did my tax jump this month?
Cumulative PAYE catches up after code changes, bonuses annualize briefly, or a W1/M1 flag appeared — the YTD columns reveal which.
What if there’s a deduction I don’t recognize?
Deductions need written authority (contract or consent) — unexplained ones are unlawful deductions, claimable via tribunal within 3 months.
Am I entitled to a payslip?
Yes — itemized, on or before payday, from day one (workers included) — with hours shown where pay varies by time worked.
✓ Formula verified • Last updated: November 3, 2026