Emergency Tax: Why It Happens and How to Claim It Back

Q: What are the emergency tax codes in 2025-26?

The main emergency tax codes in 2025-26 are: 1257L W1 or 1257L M1 (week 1 or month 1 basis — gives you the personal allowance but on a non-cumulative basis), BR (all income taxed at 20% basic rate with no personal allowance), and 0T (no personal allowance, income taxed at the full rate for each band). If you see W1, M1, BR or 0T on your payslip, you are likely on an emergency code.

Q: How long does it take to get an emergency tax refund?

Once HMRC has the correct information, your tax code is usually updated within 4 to 6 weeks. Your employer then adjusts future payslips to refund the overpayment through your pay rather than sending a separate cheque. If you have left the job, HMRC will send a P800 at the end of the tax year and pay any refund directly.

Q: How do I fix an emergency tax code?

You can update your tax code by logging into your HMRC Personal Tax Account at gov.uk, calling HMRC on 0300 200 3300, or by giving your new employer your P45 from your previous job. If you do not have a P45, complete the HMRC Starter Checklist (formerly P46) — your employer uses your answers to assign the correct code.

Emergency tax codes cause thousands of UK workers to overpay tax every month. Here is exactly what triggers it, how much extra you pay, and how to get every penny back.

What Is Emergency Tax?

Emergency tax is not a special higher rate of tax — it is the result of HMRC using a temporary tax code when your employer does not yet have the information needed to calculate your correct deductions. Because PAYE (Pay As You Earn) is designed to spread your annual tax liability across the year, an incorrect code applied to just one or two payslips can cause significant overpayments.

The most important thing to understand: emergency tax is almost always temporary and always refundable. HMRC does not keep money it was not entitled to. Every pound of emergency tax overpayment comes back to you — either through adjusted future payslips or via a direct refund at year end.

The Three Emergency Tax Codes

1257L W1 or 1257L M1 (Week 1 / Month 1 basis) — This is the most common emergency code. The "1257L" part gives you the standard Personal Allowance of £12,570, but the W1/M1 suffix means it is applied on a non-cumulative basis. Normally PAYE accounts for all your earnings and tax paid since 6 April, so any overpayment in one month is corrected in the next. With W1/M1, each pay period is treated as if it stands alone — your employer does not look back at previous months. If you earned nothing for three months and then started a new job mid-year, you would still only get one month's worth of allowance rather than the cumulative four months you are owed.

BR (Basic Rate) — All income is taxed at a flat 20% with no Personal Allowance at all. A £2,500/month gross salary taxed on BR means £500 deducted in tax. The correct deduction for someone with a standard 1257L code on £30,000/year would be approximately £248/month — so BR causes an overpayment of roughly £252 every month.

0T (Zero Personal Allowance) — The most punishing emergency code. No Personal Allowance is applied, and income is taxed across all bands from the first pound. This is typically applied when HMRC has no information at all about a new employee, or when someone has used up their allowance elsewhere. A basic-rate taxpayer on 0T pays 20% from their first pound of earnings rather than from £12,570.

When Does Emergency Tax Get Applied?

The most common triggers are:

Starting a new job without a P45 — If you cannot provide your P45 from your previous employer, your new employer must use an emergency code while HMRC assigns the correct one. Around one in five new starters experiences this.
Starting your first job ever — No employment history means no existing PAYE record. HMRC issues a code but it may take a few weeks to propagate to your payroll.
Taking money from a pension for the first time — Pension drawdown is a major source of emergency tax. When you access a pension pot for the first time, HMRC often does not know your income situation and applies a BR or 0T code to the payment. On a £20,000 lump sum, this can mean £4,000 in emergency tax instead of the correct amount (often zero if it is within the 25% tax-free allowance).
Returning to work after a gap — HMRC's records may have lapsed or the code may not have been updated.
Starting self-employment and then returning to PAYE — Switching between employment types can confuse HMRC's system.

Worked Example: The Real Cost of a BR Code

Suppose you start a new job with a gross salary of £30,000/year (£2,500/month). Your new employer applies a BR emergency code while awaiting your details.

Tax deducted on BR code: £2,500 × 20% = £500/month
Correct tax on 1257L code: (£30,000 − £12,570) × 20% / 12 = £17,430 × 20% / 12 = £290.50/month ≈ £248/month
Monthly overpayment: £500 − £248 = £252/month
After two months on BR before correction: £504 overpaid

The national average emergency tax overpayment is around £267, though pension drawdown cases regularly produce overpayments of £1,000–£3,000 on larger lump sums.

How to Fix an Emergency Tax Code

Option 1 — Provide your P45. Give your new employer the P45 from your previous job. Parts 2 and 3 go to your new employer's payroll team; they use the information to apply the correct tax code. This is the fastest route.

Option 2 — Complete an HMRC Starter Checklist. If you do not have a P45 (first job, long career gap, lost document), fill in the Starter Checklist available on gov.uk. Your answers about your employment situation allow your employer to apply the most appropriate temporary code while HMRC assigns the correct one.

Option 3 — Contact HMRC directly. Call HMRC on 0300 200 3300 (weekdays 8am–6pm) or log into your HMRC Personal Tax Account at gov.uk. You can check and update your tax code online in minutes. HMRC will then send an updated code to your employer electronically via the PAYE system.

Option 4 — Wait for the P800. At the end of each tax year, HMRC reviews all PAYE records and automatically issues a P800 tax calculation to anyone who has overpaid. If you are owed a refund, HMRC pays it directly into your bank account (if they have your details) or by cheque. This route takes the longest — potentially until after 5 April — but requires no action on your part.

Pension Drawdown: Special Emergency Tax Rules

Pension drawdown emergency tax is particularly common and often particularly large. When you take your first flexible payment from a pension pot, the pension provider applies a Month 1 code. If you take £30,000 as a lump sum, for example, the provider may deduct tax as if you were earning £360,000/year (£30,000 × 12), pushing much of it into the 40% or even 45% band. You can reclaim immediately using HMRC forms P55, P53Z or P50Z depending on whether you have emptied the pot or just taken a partial withdrawal — you do not have to wait until year end.

Related Calculators

Frequently Asked Questions

What are the emergency tax codes in 2025-26?

The main emergency tax codes are 1257L W1/M1 (week 1 or month 1 basis — gives the personal allowance but non-cumulatively), BR (all income taxed at 20% with no personal allowance), and 0T (no personal allowance, full banded rates from pound one). W1, M1, BR or 0T on your payslip signals an emergency code.

How long does it take to get an emergency tax refund?

Once HMRC has the correct information, your tax code is typically updated within 4 to 6 weeks. Your employer then adjusts future payslips to return the overpayment through pay. If you have left the job, HMRC sends a P800 after year end with any refund paid directly.

How do I fix an emergency tax code?

Give your new employer your P45, complete the HMRC Starter Checklist, or contact HMRC directly on 0300 200 3300 or via your Personal Tax Account at gov.uk. The fastest route is always providing the P45 from your previous employer.