Tax Code 1257L W1 Explained
Emergency tax code on a non-cumulative weekly basis — each pay period is taxed in isolation, so you may overpay early in the year.
At a glance — 1257L W1
- Personal Allowance
- £12,570
- Region
- UK-wide (rUK / Wales)
- Cumulative?
- No — emergency (W1 / M1 / X)
- Code type
- Standard L suffix
What does 1257L W1 mean?
You are entitled to the standard tax-free Personal Allowance. This is the most common tax code suffix.
Your tax-free Personal Allowance is £12,570.
This is an emergency tax code. You may be paying more tax than necessary. Contact HMRC to get your correct tax code.
How much tax will you pay on 1257L W1?
Annual income tax HMRC would deduct on 2025-26 rates for a range of salaries, assuming the full year on this code. National Insurance is additional and the same across the UK.
| Annual salary | England / Wales / NI — income tax | Effective rate | Take-home (pre-NI) |
|---|---|---|---|
| £20,000 | £1,486 | 7.4% | £18,514 |
| £30,000 | £3,486 | 11.6% | £26,514 |
| £50,000 | £7,486 | 15.0% | £42,514 |
| £80,000 | £19,432 | 24.3% | £60,568 |
| £100,000 | £27,432 | 27.4% | £72,568 |
For Scottish / rUK side-by-side, or to model your own salary, student loan and pension contributions, use the tax code checker.
Should you be on tax code 1257L W1?
Emergency codes (W1, M1, X) usually appear when starting a new job without a P45, or after a gap in employment. They can cause short-term overpayment because HMRC treats each pay period in isolation. Send your P45 or complete a Starter Checklist to switch back to a cumulative code and claim any refund through PAYE.
Why you have this code
- You started a new job without handing over a P45 from your previous employer
- You gave incomplete answers on the Starter Checklist
- HMRC placed you on a temporary non-cumulative basis while your record is set up
How to fix it if 1257L W1 is wrong
- Check your current code in the HMRC app, your Personal Tax Account, or your latest P2 coding notice or payslip.
- New job with no P45? Ask your employer for a Starter Checklist — completing it correctly is what moves you off a temporary code.
- Not sure what your P45 figures mean, or already overpaid? See the P45 box-by-box guide to decode what your employer reported, or run the tax refund estimator to check what you might be owed.
- If HMRC agrees your code was wrong, most in-year corrections refund automatically through payroll; larger over- or underpayments are settled via a P800 calculation after the tax year ends.
Because 1257L W1 is a non-cumulative emergency basis (W1 / M1), fixing it doesn't retroactively refund tax already deducted — HMRC releases the refund once your code is corrected, either through payroll or a P800.
Related tax codes
1257L — Standard
The default HMRC tax code for most UK employees — gives you the full £12,570 tax-free Personal Allowance.
1257L M1 — Emergency (Monthly)
Emergency tax code on a non-cumulative monthly basis — each month is taxed as if it were 1/12 of the year.
S1257L — Scottish Standard
The Scottish version of the standard code. Same £12,570 allowance, but Scottish tax bands (19% / 20% / 21% / 42% / 45% / 48%) apply.
C1257L — Welsh Standard
The Welsh version of the standard code. Full £12,570 allowance with Welsh (rUK-aligned) rates.
FAQ
Will W1 correct itself automatically?
Usually yes — once your employer receives your P45 or a Starter Checklist confirmation from HMRC, you move onto a cumulative 1257L code and any overpaid tax is refunded through payroll.
Why does W1 mean I might overpay tax?
W1 taxes each week in isolation rather than spreading your Personal Allowance evenly across the year, so early pay periods can be taxed more heavily than under a cumulative code.
Check your own code: enter any HMRC tax code into the free tax code checker — it decodes the letters and number, shows your Personal Allowance, and estimates your take-home using 2025-26 or 2026-27 rates.
For the full plain-English guide to every UK tax code letter, prefix and suffix, see UK Tax Codes Explained 2026-27.
Sources
Tax code rules from gov.uk/tax-codes. Income tax rates from HMRC. Effective tax figures computed live from central configuration — correct for 2025-26.