New job, first payslip, hundreds of pounds lighter than expected — the culprit is almost always an emergency tax code. It is fixable, usually automatic, and easier to tolerate once you understand what HMRC is doing.
Why It Happens
Without your P45 or full history, payroll cannot know your year-to-date position. So HMRC applies a holding code until the record catches up — protecting the Treasury first and reconciling later.
The Codes Decoded
- 1257L W1/M1: normal allowance but non-cumulative — each pay period judged in isolation, ignoring unused allowance from earlier months
- 0T: no personal allowance at all — every pound taxed from the first
- BR: flat 20% on everything — standard for second jobs, wrong for your main one
- D0/D1: flat 40%/45% — again, second-income codes
Getting Your Money Back
Once the correct cumulative code lands (P45 processed, or starter checklist filed), the refund arrives automatically through your next payslip — the cumulative system recalculates the whole year and returns the excess in one go. To speed it up: chase your P45, complete the starter checklist accurately, and check your code in HMRC’s Personal Tax Account, where you can correct estimated income yourself.
Left the Country or Stopped Working?
Mid-year leavers often overpay with no future payslip to refund through — claim directly via form P50 instead of waiting for year-end reconciliation.