1257L Tax Code Explained

1257 represents the standard £12,570 annual Personal Allowance for 2026/27. Payroll uses tax-code tables and period rounding, so dividing this amount by 12 gives an illustration rather than a guarantee of exact monthly tax.

The allowance is frozen at £12,570 through 2030/31 under the published threshold policy. Your own code can still change because of income, benefits or other adjustments.

In England, Wales and Northern Ireland, someone entitled to the full allowance pays 20% on the next £37,700 of taxable income. Scotland has different rates and bands. The allowance starts to taper when adjusted net income exceeds £100,000.

L indicates entitlement to the standard Personal Allowance category. It does not prove that the code contains no adjustments. For example, 1100L can reflect a reduced tax-free amount while retaining L.

Read the number, any country prefix and any W1, M1 or X marker together. HMRC's coding notice explains adjustments; the letter alone cannot establish whether the underlying records are correct.

1257L is commonly used where the full standard allowance is allocated to one employment and no net coding adjustment is required. Scotland and Wales use S1257L and C1257L equivalents.

It is possible to receive taxable benefits and still have 1257L if those benefits are taxed through payroll rather than collected by reducing the code. Having one job or earning below £100,000 does not, on its own, establish which code HMRC should issue.

Several events can cause HMRC to move you away from a straightforward 1257L code:

• Earning over £100,000: The personal allowance tapers by £1 for every £2 of adjusted net income above £100,000. At £110,000 your effective allowance is £7,570 (code 757T). At £125,140 it reaches zero. HMRC typically issues a 0T or T code once this threshold is crossed.
• Marriage allowance registration: If you transfer 10% of your personal allowance to your partner, your code becomes 1131N (£12,570 minus £1,260 = £11,310, code number 1131). If you receive the transfer, your code becomes 1383M.
• Benefit in kind: A £3,000 taxable company-car benefit collected through your code, rather than payrolled, could reduce a £12,570 tax-free amount to £9,570 (957L), assuming no other adjustments. Larger benefits can reduce the number much further, and if they exceed the allowance entirely the code changes to a K code.
• Prior-year underpayment: A £500 tax debt is not the same as a £500 allowance reduction. At a 20% tax rate, collecting £500 over a full year would need about £2,500 less tax-free pay: £12,570 − £2,500 = £10,070, illustrated by 1007L. A £500 allowance reduction would collect only £100 at 20%. HMRC calculates the actual adjustment using your circumstances.
• State pension: The state pension is taxable but paid without deduction. HMRC reduces your PAYE code to collect the tax, resulting in a lower code number.

When you see your code written as 1257L W1 or 1257L M1, the suffix changes how the code is applied. W1 means week 1 basis; M1 means month 1 basis. Both are forms of the non-cumulative emergency basis.

Normally, PAYE accumulates across the tax year. Each pay run considers all the pay and tax from 6 April to the current date, correcting any under- or overpayment automatically. Under W1/M1, each pay period is treated in isolation: you receive exactly one week's or one month's worth of the personal allowance for that period, and no look-back at previous periods is performed.

This matters because if you join a new employer in, say, month 8 of the tax year, the non-cumulative basis means you do not receive credit for the seven months of allowance you have already used (or not used) elsewhere. The result can be either too much or too little tax depending on your circumstances.

W1/M1 codes are typically issued when:

• You start a new job without a P45.
• HMRC issues a new code mid-year and does not want a large catch-up adjustment in a single pay run.
• There is uncertainty about your income position that HMRC is still resolving.

HMRC decides when the code and basis should change. If payroll receives a cumulative code and complete earlier pay and tax, it can recalculate the year-to-date position. Any refund route depends on those records, the tax year and whether you use Self Assessment.

Here is how the numbers work for an employee earning £30,000 a year (£2,500 gross per month) on code 1257L, paid monthly, in 2026–27.

Each month, the personal allowance is spread evenly: £12,570 ÷ 12 = £1,047.50 tax-free pay per month.

Taxable pay each month: £2,500.00 − £1,047.50 = £1,452.50.

Income tax at 20%: £1,452.50 × 20% = £290.50.

Employee National Insurance (8% on earnings between the Primary Threshold of £1,048/month and the Upper Earnings Limit of £4,189/month): (£2,500 − £1,048) × 8% = £1,452 × 8% = £116.16.

Approximate monthly net pay: £2,500.00 − £290.50 − £116.16 = £2,093.34 (before any pension, student loan, or other deductions).

Annual income tax: £290.50 × 12 = £3,486. Annual NI: approximately £1,394. Total deductions approximately £4,880 from a gross of £30,000, leaving take-home of approximately £25,120.

Assume England in 2026/27, standard allowance, NI category A and no pension, loans or other adjustments. £50,000 remains below the £50,270 higher-rate threshold: the taxable salary fits in one tax band.

• Annual taxable income: £50,000 − £12,570 = £37,430.
• Annual Income Tax: £37,430 × 20% = £7,486.
• Annual-threshold NI estimate: £37,430 × 8% = £2,994.40.
• Annual take-home estimate: £39,519.60.

For an actual £4,166.67 monthly payment, category A NI using the £1,048 monthly primary threshold is (£4,166.67 − £1,048) × 8% = £249.49. Monthly payroll and annual-threshold estimates can differ slightly.

At £52,000, only the slice above £50,270 attracts 40% Income Tax. The higher rate reduces the net gain from that slice; it does not reduce total take-home below the £50,000 result under these assumptions.

Check the coding notice if adjusted net income is above £100,000, Marriage Allowance applies, taxable State Pension needs collecting through PAYE, or benefits are being collected through your code.

Check multiple employments too: using the full allowance twice can undercollect tax, while an allowance can legitimately be allocated or split between sources. A payrolled benefit does not automatically require a lower code.

Use the wrong-code checklist to verify the underlying income and benefit records with HMRC.

Compare your payslip using the tax year, pay frequency, pension method, loans and any non-cumulative marker actually shown. A calculator match supports the arithmetic under those inputs; it does not prove that you are entitled to that allowance or that HMRC's records are right.

Ask payroll about year-to-date adjustments, the code notice received and taxable benefits. Check your employment and income details in your HMRC personal tax account if the code itself appears wrong. A correction takes effect when payroll receives and applies the notice; ask which pay run that will be.