Emergency Tax Codes Explained 2026/27
Codes like BR, 0T, and 1257L W1 mean you're almost certainly overpaying income tax. Here's what each code means, exactly how much it's costing you, and the fastest way to get your money back.
The emergency codes — what each one means
There are four common emergency tax codes in the UK. Each one represents a different level of overpayment. Check your payslip and find which applies to you:
⚠ BR — Basic Rate, no personal allowance
Every penny you earn is taxed at 20% with zero tax-free allowance. The most expensive emergency code. It is correct only if this is a second job where your full allowance is already used at another employer. If it's on your main job, you're losing £2,514/year.
⚠ 0T — No allowance, all bands apply
Like BR but worse for higher earners: you pay 20% up to £50,270, then 40% on income above that — all from the first pound. Often used when an employer has no starter information at all. Never correct for a single main job.
⚠ 1257L W1 — Week 1 non-cumulative basis
You do get your personal allowance (£12,570/year), but it's applied one week at a time instead of being tracked cumulatively. If your pay fluctuates or you started mid-year, you'll overpay. The "W1" suffix is the problem — it should just read "1257L".
⚠ 1257L M1 — Month 1 non-cumulative basis
Same as W1 but applied monthly. Your allowance resets each month rather than being tracked across the year. Very common at the start of a new job.
The cost of emergency tax — real numbers
The BR code is the most common and most expensive. Here's what it costs vs. the correct 1257L code across different salary levels. These are annual figures.
| Salary | Tax on correct 1257L | Tax on BR (emergency) | Annual overpayment |
|---|---|---|---|
| £20,000 | £1,486 | £4,000 | £2,514 |
| £30,000 | £3,486 | £6,000 | £2,514 |
| £40,000 | £5,486 | £8,000 | £2,514 |
| £50,000 | £7,486 | £10,000 | £2,514 |
| £60,000 | £11,432 | £14,000 | £2,568* |
* Above £50,270 the 0T code can cost more than BR due to the higher rate band applying. Figures are income tax only, 2026/27 rates.
Emergency tax at a new job — the Starter Checklist
Emergency codes almost always happen at a new job when the employer doesn't have your P45. If you can't provide a P45, your employer should give you a Starter Checklist (formerly called a P46). Completing this accurately prevents most emergency tax situations.
The checklist asks you to tick one of three statements (A, B, or C):
Statement A — tick this if:
This is your first job since April 6th, OR you've been self-employed, OR you've been claiming benefits. Your employer will use code 1257L on a cumulative basis — the most favourable option.
Statement B — tick this if:
This is your only job and you had another job earlier in the tax year that has ended. Your employer uses 1257L on a Week 1/Month 1 basis until HMRC confirms your full year position.
Statement C — tick this if:
You have another job or pension alongside this one. Your employer will apply the BR code — all earnings taxed at 20% as your personal allowance is used elsewhere. This is correct for a second job.
What happens if it's not fixed before April 5th?
If the tax year ends (April 5th) before your emergency code is fixed, HMRC won't automatically send you a refund — you need to take action. Here's what happens:
📬
P800 letter (June–October)
HMRC reviews all PAYE income and sends a P800 tax calculation if they think you overpaid. You can claim the refund online or by post.
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Claim via Personal Tax Account
Don't wait for the P800. Log into gov.uk/personal-tax-account, check your Income Tax for the year, and request a refund directly.
📞
Call HMRC directly
Call 0300 200 3300 with your NI number and P60 or final payslip for the year. HMRC can process refunds by bank transfer, usually within 5 working days.
4-year time limit: You can claim overpaid income tax going back up to 4 full tax years. So in the 2026/27 tax year, you can claim back to 2022/23. Don't leave it too late.