How Much Emergency Tax Will I Pay? Codes, Pensions, and Refunds

How much emergency tax you will pay depends on the code your employer or pension provider uses and how big the single payment is. On the standard 2026-27 monthly emergency code (1257L M1), the first £1,047.50 of each payment is tax-free, the next £3,141.67 is taxed at 20%, the next £6,239.17 at 40%, and anything above £10,428.33 at 45%.¹ The system almost always overtaxes you in the short term because it treats each payslip in isolation, but the excess normally comes back once HMRC issues the right code.

Why the Bill Looks So High

Emergency tax is non-cumulative. A normal tax code tracks your year-to-date pay and tax from 6 April, so each payslip accounts for everything before it. An emergency code throws that running total out. Each pay period is treated as if you will earn that same amount every period for the rest of the year, and the annual allowances and bands are sliced into equal monthly (or weekly) chunks.

For 2026-27 the Personal Allowance stays frozen at £12,570, the basic rate band covers the next £37,700, and the higher rate band runs up to £125,140.¹ Divide each by twelve and you get the monthly emergency thresholds shown above. On a weekly code (W1), divide by 52 instead.

You can spot the emergency version of the standard code on your payslip by the suffix: 1257L W1 for weekly pay, 1257L M1 for monthly, or 1257L X where pay dates vary. Without one of those suffixes, plain 1257L is just the normal code for a person with one job and no adjustments.²

Two Worked Examples

Take a £3,000 monthly payment on 1257L M1. The first £1,047.50 is tax-free. The remaining £1,952.50 falls inside the monthly basic rate slice and is taxed at 20%, giving £390.50 of income tax that month. On a cumulative code partway through the year, unused allowance from earlier months would soak up much of that, and the deduction could be far smaller or nothing.

Now take £6,000 in a single month. The first £1,047.50 is tax-free. The next £3,141.67 is taxed at 20% (£628.33). The remaining £1,810.83 falls into the 40% slice (£724.33). Total for the month: £1,352.66.³ Once HMRC sees your actual annual position, most of that 40% element is likely to disappear.

The Codes That Take More

1257L with a W1, M1, or X is the gentlest of the emergency codes because it still gives you a share of the Personal Allowance. Others do not:

BR taxes everything from that job at 20% with no personal allowance. HMRC uses it when it thinks another job or pension is already using your allowance.⁴
0T also gives no personal allowance, but income can flow into the 40% and 45% bands. HMRC applies it when your allowance is used up elsewhere or when it has no details about you.⁴
D0 taxes everything from that source at 40%. It is normal on a second job when the first job already uses the whole basic rate band, but wrong as the code on your only job.⁴

Pension Withdrawals Are the Worst Case

Flexible pension withdrawals are where emergency tax hits hardest. The provider usually has no picture of your other income, so it applies the same non-cumulative logic: one-twelfth of the allowance is deducted, then the rest is sliced across the bands as if you were going to take the same amount every month for the rest of the year.

The bands used on a monthly emergency basis for pensions are the first £1,048 tax-free, the next £3,142 at 20%, the next £7,287 at 40%, and everything above £11,477 at 45%. Take £30,000 in one hit and the system taxes it as though you were going to take £30,000 a month, pushing a large slice into 40% and 45%. The true bill, once HMRC sees your full-year income, is usually far lower. If you know a big one-off withdrawal is coming and you would rather not wait for the refund, ask the provider whether it can request a tax code from HMRC first. Not all providers will.

If You’re a Scottish Taxpayer

Scottish emergency codes start with an S, such as S1257L M1. The S tells the employer to apply Scottish income tax rates, which differ from the rest of the UK. For 2026-27, Scotland has six bands: a 19% starter rate on income up to £16,537, a 21% intermediate rate, a 42% higher rate, a 45% advanced rate, and a 48% top rate on income above £125,140. Welsh taxpayers see a C prefix but currently pay the same rates as England and Northern Ireland.²

Getting Off the Emergency Code

Emergency tax usually resolves itself within a few pay periods. Once your employer sends payroll data to HMRC and HMRC has your P45 or Starter Checklist details, a new coding notice goes to your employer. From that point payroll switches to a cumulative basis and adjusts for any overpayment. The next payslip normally shows a smaller deduction or a refund built in.

If weeks go by without a change, use the “Check your Income Tax” service on GOV.UK. You can see your current code, update your employment details, and tell HMRC about anything that affects the code. A Government Gateway account is needed, and first-time users may have to prove identity with photo ID.⁵ You can also phone HMRC.

Claiming Back What You Overpaid

Most overpayments come back through payroll automatically once your correct code is in place: the cumulative recalculation spreads the refund across your remaining pay periods in the tax year.

If the tax year ends on 5 April before things are corrected, HMRC sends a P800 tax calculation or a Simple Assessment letter, typically between June and October. It shows what you paid against what you actually owed.⁶

Two ways to collect a refund after a P800. The online bank transfer service is faster: you need the reference number from the letter and your National Insurance number, and money usually arrives within five working days. A cheque requested online takes around six weeks. If the P800 says HMRC will send a cheque automatically, it should arrive within 14 days of the letter’s date and you don’t need to do anything.⁷

1
GOV.UK. Income Tax Personal Allowance and the Basic Rate Limit, and Certain National Insurance Contributions Thresholds From 6 April 2026 to 5 April 2028
2
GOV.UK. Emergency Tax Codes
3
GOV.UK. Income Tax Rates and Personal Allowances
4
GOV.UK. Tax Codes: What Your Tax Code Means
5
GOV.UK. Check Your Income Tax for the Current Year
6
GOV.UK. Tax Overpayments and Underpayments
7
GOV.UK. Tax Overpayments and Underpayments: If Your Tax Calculation Letter (P800) Says You’re Due a Refund