// Source citations for the factual claims in this guide (kept out of the // rendered tree: flow-level MDX comments break Next scroll-on-navigation). export const sources = [ "source: https://www.gov.uk/tax-codes/emergency-tax-codes (retrieved 2026-06-12): emergency codes end W1, M1 or X; "your tax is worked out based on what you're paid in that week or month only"; HMRC usually updates the code once it has details from your new and previous employers, which "can take up to 35 days from when you start your job".", "Calculation basis: 2026/27 figures in site/lib/tax/config.ts (PA £12,570, basic 20% on first £37,700 of taxable income, higher 40%), verified in-repo 2026-06-10 against gov.uk. £10,000 on 1257L M1: taxable £8,952.50; £3,141.67 at 20% = £628.33; £5,810.83 at 40% = £2,324.33; total £2,952.67.", "source: https://www.gov.uk/tax-overpayments-and-underpayments and /if-youre-due-a-refund (retrieved 2026-06-12): P800 letters sent June to March of the following tax year; online bank transfer ~5 working days; cheque up to 6 weeks, automatic cheque within 14 days.", "source: https://www.gov.uk/guidance/claim-back-tax-on-a-flexibly-accessed-pension-overpayment-p55 (retrieved 2026-06-12): P55 for partial access with no further payments this year; P53Z for fully accessed pots; P50Z for fully accessed pots after stopping work.", ];

Guide · 4 minute read

How do I get emergency tax back?

Most emergency tax comes back automatically: HMRC corrects your tax code and the refund lands in a later payslip. If it does not, claim it from HMRC through your personal tax account (the P800 route), or with form P55, P53Z or P50Z for pension withdrawals.

What an emergency tax code actually is

An emergency code is a tax code ending in W1 (weekly pay), M1 (monthly pay) or X (irregular pay dates), so for 2026/27 the usual versions are 1257L W1, 1257L M1 or 1257L X. Some payroll software shows it as "NONCUM" instead. You typically get one when you start a job without a P45, or when you take a first flexible pension withdrawal and the provider has no up-to-date code for you.

The number is normal; the suffix is the problem. PAYE usually works cumulatively, looking at your whole year so far and smoothing things out. An emergency code switches that off: each payday is taxed in isolation, as if that week's or month's pay is what you earn every period of the year. You still get a slice of the personal allowance each period (£12,570 a year is £1,047.50 a month), but the system cannot look backwards, so it never corrects itself. You can run your numbers both ways in our take-home pay calculator.

How much extra it costs

Two situations dominate, and they hurt very differently.

New starters. If 1257L M1 is on your first payslip and your pay is steady, the monthly deduction is roughly right going forward. What you lose is the catch-up: any allowance you did not use earlier in the tax year. Each unused month of allowance is worth up to £209.50 back at the basic rate (20% of £1,047.50). Start your first job of the year in September and you have five unused months behind you, so around £1,047.50 sits with HMRC until the code is fixed.

Pension withdrawals. This is where emergency tax gets expensive, because the month 1 basis treats a one-off lump sum as a regular monthly income. Take £10,000 of taxable pension cash and the provider taxes it as if you receive £10,000 every month, £120,000 a year. Roughly £3,140 of it gets the 20% rate, most of the rest gets 40%, and about £2,950 is deducted. If that withdrawal is your only taxable income for the year, the correct bill is zero (it sits below the £12,570 personal allowance), so nearly all of it is yours to reclaim.

Route 1: the automatic PAYE correction

For employees, this is the default and it usually just works. HMRC matches up the details from your new and old employers (a P45 speeds this up considerably) and issues a proper cumulative code to you and your employer. Gov.uk says this can take up to 35 days from when you start the job. Because the replacement code is cumulative, your employer's next pay run recalculates your whole year to date and any overpayment comes back in that payslip, with no claim needed.

So the first move is simply to check what code you are on; our tax code checker decodes the letters and flags emergency suffixes. If the W1, M1 or X is still there two payslips after HMRC should have your details, chase it: update your employment details in your personal tax account or call HMRC, because the automatic fix only happens once the code changes.

Route 2: claiming from HMRC yourself

If the year ends before the code is corrected, HMRC reviews PAYE records and sends a P800 calculation letter to people who overpaid, between June and March of the following tax year. The letter tells you how to claim: online by bank transfer (about 5 working days), via the personal tax account or HMRC app, or by cheque (up to 6 weeks, or within 14 days if the letter says one is coming automatically).

Pension withdrawals are the exception: do not wait. If you took a one-off withdrawal, there is no string of future payslips for PAYE to correct through, so claim in-year with the right form: P55 if you accessed part of the pot and are not taking further payments this tax year, P53Z if you emptied the pot, or P50Z if you emptied it and have stopped working. HMRC works out the repayment from the form rather than refunding the moment of overpayment automatically.

Avoiding it next time

Hand your new employer a P45, or complete their starter checklist carefully on day one, before the first payroll cut-off. For pensions, a common tactic is to make a small first withdrawal (say £100) to force the provider onto a proper tax code before taking the real lump sum. It costs a few weeks of waiting and can save a four-figure wait for a refund.

Common questions

How long does it take HMRC to fix an emergency tax code?

Gov.uk says HMRC usually updates the code once it has details from your new and previous employers, which can take up to 35 days from starting the job. Handing over a P45 speeds it up. Once the new cumulative code is applied, the refund arrives in your next payslip.

Will emergency tax be refunded automatically?

For employees, usually yes: the corrected code triggers a payroll recalculation and the money comes back through wages. If the tax year ends first, HMRC sends a P800 letter between June and March of the following year. One-off pension withdrawals are the exception; claim in-year with form P55, P53Z or P50Z.

Why was my pension withdrawal emergency taxed?

A first flexible withdrawal is usually taxed on a month 1 basis, which treats the lump sum as a regular monthly income. A £10,000 taxable withdrawal is taxed as if you earn £120,000 a year, deducting roughly £2,950 even when the correct bill may be far lower or zero.

What is the emergency tax code for 2026/27?

1257L W1, 1257L M1 or 1257L X, reflecting the standard £12,570 personal allowance. The number is fine; the W1, M1 or X suffix means each payday is taxed in isolation rather than cumulatively. Some payslips show it as NONCUM.

Do I need a P45 to avoid emergency tax?

It is the cleanest route, but not the only one. Without a P45, complete your new employer's starter checklist before the first payroll deadline so HMRC can issue a proper code quickly. Skipping both is what usually lands you on an emergency code.

Guidance and education, not regulated financial advice.