Skip to main content
2026/27 Tax Year

Emergency Tax and Refund Checker

Use this when a new job, first payslip, missing P45 or strange code has left you wondering whether HMRC or payroll has taken too much. It compares a common emergency-code outcome with a normal cumulative 1257L position and shows the likely refund route.

Common trigger: emergency tax often appears when payroll does not yet have enough information, especially after a job change. GOV.UK says employers should usually use the starter checklist if a P45 is not available.

Your payslip setup

This is a first-pass estimator for the tax side only. National Insurance and payroll timing quirks are intentionally left out.
Estimated overpaid tax so far
£0 Current-code tax on this payslip: £0
Estimated tax on this payslip using the current code£0
Normal cumulative tax due to date on 1257L£0
Tax recorded to date after this payslip£0
Difference versus normal cumulative code£0
Likely statusNo obvious issue
Likely refund routeNo refund path needed
Current-code meaningCurrent code type explained here

What this means

A week 1 or month 1 code ignores earlier pay and tax. That can be harmless for a short period, but if payroll never receives the correct data it can leave you temporarily over or under taxed.

Tax code guide

Worked examples — see the math on real numbers

How emergency tax codes work and when refunds happen automatically vs need claiming.

Sam — left old job, new job started mid-tax-year, no P45

New monthly salary£3,500 gross
Tax code applied (no P45)1257L M1 (emergency, monthly)
Months worked4 (Aug-Nov 2026)

The math:

  1. Emergency M1 treats each month independently — no cumulative allowance
  2. Per month: (£3,500 − £1,047 monthly PA) × 20% = £490 income tax
  3. Total tax over 4 months: £1,960
  4. Correct cumulative position (assuming this is the only 2026/27 income): annual £14,000 − £12,570 PA = £1,430 × 20% = £286
  5. Over-payment: £1,960 − £286 = £1,674

Result: Sam over-pays £1,674 by November. Once HMRC reconciles via the new employer's RTI submissions (usually after 2-3 months), the tax code switches to 1257L cumulative and a refund is processed automatically through payroll — usually visible by January's payslip.

Maria — multiple jobs, BR code mistakenly applied to main

Main job£40,000 (code BR)
Side job£8,000 (code 1257L)
Tax year2026/27

The math:

  1. BR on main job: £40,000 × 20% = £8,000 (no Personal Allowance)
  2. 1257L on side: £8,000 − £8,000 of allowance used = £0
  3. Total tax deducted: £8,000
  4. Correct: combined income £48,000 − £12,570 PA = £35,430 × 20% = £7,086
  5. Over-payment: £914

Result: Maria's codes are swapped — main job should have 1257L (with the bigger allowance), side job should be BR. Calling HMRC fixes the codes within 4-6 weeks; refund of £914 either comes through payroll once codes are correct, or via P800 after tax year end. Always check which job has 1257L.

Figures use 2026/27 UK tax-year rates and thresholds. Always verify against your specific payslip or tax statement before acting.

Editorial accountability
Open Trust Centre →

Every page is reviewed against the editorial standards, written from primary sources, sourced openly, and corrected publicly. No affiliate revenue. No sponsored content. No paid placements.

Editorial standards Editorial process Corrections policy How we make money Editorial team Methodology

How this checker works

This page compares two things: the estimated tax effect of the current code on this payslip, and the cumulative tax due to date if the same pay had instead been processed on a standard 1257L cumulative code for 2026/27.

Sources and practical route

GOV.UK emergency tax codes GOV.UK tax codes overview HMRC PAYE starter checklist guidance GOV.UK claim a tax refund

If the code is genuinely temporary and payroll later receives the correct details, the correction often happens automatically through payroll. If it does not, the refund can instead flow through a Personal Tax Account claim, a P800 reconciliation, or Self Assessment if you already file.