1250L Tax Code: Why It Became 1257L and How to Check Yours

The 1250L tax code was the standard UK tax code for the 2020/21 tax year. It meant you were entitled to a Personal Allowance of £12,500, the amount you could earn before paying income tax. If you’re seeing 1250L on an old P60, P45, or payslip from that year, that’s all it is telling you. If you’re seeing it on a current payslip, it’s out of date: the standard code is now 1257L, matching the £12,570 Personal Allowance, which is frozen at that level until April 2031.¹

What the Number and the Letter Mean

A tax code is your Personal Allowance with the last digit removed, followed by a letter that flags your situation. Under 1250L, the 1250 stood for £12,500 of tax-free income. Under the current 1257L, 1257 stands for £12,570.² Your employer’s payroll software reads that number and shields the right slice of your pay from tax each pay period.

The letter L confirms you get the standard Personal Allowance with no special circumstances attached.³ It’s the most common suffix and fits most people with a single job or pension. Other letters, and prefixes like S or K, signal that something about your tax picture is different, and they change the arithmetic.

Why 1250L Was Replaced by 1257L

The Personal Allowance rose from £12,500 to £12,570 in April 2021. The standard code updated at the same time, from 1250L to 1257L. Because the allowance is frozen at £12,570 until at least April 2031, 1257L will remain the default for years to come.¹

So if 1250L is showing on a payslip issued after April 2021, something is off. Either your employer is running old information or HMRC didn’t send an updated coding notice through. The direct cost is small: you’d be taxed on £70 of income that should be tax-free, which is £14 a year at the basic rate. But an old code on a current payslip can be the visible edge of a bigger error worth checking.

How the Code Turns Into Take-Home Pay

Your employer spreads the Personal Allowance evenly across the year, so you’re not left waiting for a lump-sum reckoning in April. On 1257L, monthly-paid employees get roughly £1,048 tax-free each month, and weekly-paid workers get about £242 before tax kicks in.² Anything above those thresholds is taxed according to the rate bands.

For the 2026/27 tax year, the bands for most of England, Wales, and Northern Ireland are:

Basic rate of 20% on taxable income up to £37,700 above the Personal Allowance
Higher rate of 40% on taxable income from £37,701 to £125,140
Additional rate of 45% on taxable income above £125,140

Each rate applies only to the slice of income falling within that band, not to your whole salary.⁴

Scotland runs its own bands and rates, and Scottish taxpayers carry an S prefix on the code (for example, S1257L) so employers apply the Scottish rates.⁵

Cumulative and Non-Cumulative Codes

Most codes run cumulatively. Your employer tracks total pay and total tax from the start of the tax year, and each pay period recalculates against the running total. If you earn less one month, the next payslip may quietly refund a small amount. It keeps your tax roughly right without you doing anything.

A non-cumulative code shows W1 (weekly) or M1 (monthly) after the number. It treats each pay period on its own and ignores what came before. HMRC uses this as a stopgap when they don’t have enough information to run the cumulative sum, often after you start a job without a P45. The risk is that you may over- or underpay across the year, because the system can’t smooth things out.⁶

When Your Code Won’t Be the Standard One

HMRC assigns a different code whenever your situation doesn’t fit the default. These are the ones you’re most likely to see:

BR taxes every pound from that source at the basic rate 20% with no allowance. It’s the normal code for a second job, because your allowance is already used by the main employer.
D0 taxes everything at 40%. It’s used for a second income source when the basic rate band is already exhausted by your primary earnings.
0T means your Personal Allowance has been used up, or your new employer doesn’t yet have the details needed to assign a proper code.²
A K prefix means deductions and taxable benefits exceed your Personal Allowance, so tax is effectively added to income rather than subtracted. Typical triggers include a tax debt being collected through your wages, taxable state benefits, or a company car. Your employer can never deduct more than half your pre-tax pay under a K code.⁷
An M suffix means you’re receiving a Marriage Allowance transfer from your spouse or civil partner, adding £1,260 to your allowance (giving something like 1383M).
An N suffix means you’ve transferred £1,260 of your allowance to your partner, reducing yours (giving something like 1131N).

One quick sanity check: if you have only one job and your code is BR, D0, or 0T, that’s almost certainly wrong. Your whole salary is being taxed without any allowance, and you’re likely owed a refund. Contact HMRC rather than waiting for the tax year to close.

How to Check Your Code and Fix It

The fastest route is the “Check your Income Tax” service on GOV.UK. You’ll need a Government Gateway account, which involves verifying your identity with photo ID like a passport or driving licence.⁸ Once you’re in, you can see every active code across your jobs and pensions, the income estimates HMRC is working from, and any adjustments built into your code. You can update estimated income or report changes directly in the same service.

If you’d rather phone, HMRC’s Income Tax helpline is 0300 200 3300, Monday to Friday, 8am to 6pm. Have your National Insurance number to hand.⁹

Before you challenge a code, get your paperwork together. Your P60 summarises pay and tax for the previous year, a P45 covers earnings so far if you’ve recently left a job, and a P11D lists taxable benefits from your employer such as a company car or private medical cover.¹⁰ Taxable benefits reduce your Personal Allowance, so your code number will be lower than 1257 by the value of those benefits. Compare that expected number to what your payslip shows. If they don’t line up, report it.

If You’ve Paid the Wrong Amount

After each tax year closes on 5 April, HMRC compares what you actually earned against the tax collected. When the two don’t match, they send a P800 tax calculation letter, or a Simple Assessment for larger sums, sometime between June and the following March.¹¹

If the P800 shows you overpaid, you’re owed a refund. Where the letter says you can claim online, a bank transfer usually arrives within five working days, or a cheque takes about six weeks. If HMRC issues the refund automatically, expect a cheque within 14 days of the date on the letter. Refunds covering multiple years come as a single payment.¹²

Underpayments of £3,000 or less are normally collected by adjusting the following year’s tax code, spreading the recovery across future pay packets. Owe more than that, and HMRC sends a Simple Assessment, which you pay directly.¹¹ The usual causes are the wrong code, a second job started mid-year, or taxable state benefits that weren’t factored in. Spotting a bad code mid-year and getting it fixed keeps the balance from growing.

1
GOV.UK. Income Tax: Maintaining the Personal Allowance and the Basic Rate Limit
2
GOV.UK. Tax Codes: What Your Tax Code Means
3
Royal London. Tax Codes Explained
4
HM Revenue & Customs. Income Tax Rates and Allowances for Current and Previous Tax Years
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GOV.UK. Income Tax in Scotland: Current Rates
6
HM Revenue and Customs. PAYE Manual – Coding: Ways an Employer Can Operate a Code
7
GOV.UK. Tax Codes: If You Have a K in Your Tax Code
8
GOV.UK. Check Your Income Tax for the Current Year
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GOV.UK. Income Tax: Enquiries
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GOV.UK. Your P45, P60 and P11D Form: Why You Get Each Form
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GOV.UK. Tax Overpayments and Underpayments
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GOV.UK. Tax Overpayments and Underpayments: If Your Tax Calculation Letter (P800) Says You’re Due a Refund