Tax Codes Explained 2026/27 — 1257L, BR, D0 & K

Your tax code is the number and letter on your payslip that tells your employer how much tax-free pay to give you each period — and it is how HMRC collects most income tax without you ever filing a return. For 2026/27 the standard code is 1257L, built on the £12,570 personal allowance: the digits are the allowance divided by 10, and the letter L means you qualify for the standard allowance. Check your take-home pay against your code with the Salary Calculator→.

This guide explains every common code, what the letters mean, why codes go wrong, emergency codes, and how to correct yours online.

The Anatomy of a Tax Code

Every code has two parts: a number that represents your tax-free amount in pounds divided by 10, and a letter that says which allowance rules apply. HMRC works out your total allowances — the personal allowance plus anything extra like Blind Person's Allowance — subtracts adjustments such as taxable benefits or underpaid tax from previous years, and divides by 10. A code of 1257L therefore means £12,570 of tax-free income; if your employer also reported a company car, HMRC reduces the number to claw back the benefit through PAYE.

BR, D0, D1 and K Codes

A BR code means your personal allowance is already being used elsewhere — typically by your main job — so this employment taxes everything at 20%. D0 and D1 do the same at 40% and 45%, ensuring your second income is taxed at roughly the right marginal rate without splitting the allowance. K codes are the reverse: your deductions (taxable benefits, State Pension, underpaid tax from a prior year) exceed your allowances, so HMRC adds the K figure to your taxable pay. K497 adds £4,970 of notional income; the tax deducted under a K code is capped at 50% of pay in a pay period. A K code is often correct — check the underlying calculation before assuming an error.

Emergency Codes and Multiple Jobs

When you start a job without a P45, employers may use 1257L W1 (weekly) or 1257L M1 (monthly) — the allowance is applied to each pay period in isolation with no look-back, so seasonal workers can be overtaxed. 0T gives no allowance at all. Emergency codes can be corrected once HMRC has the missing employment details; if they persist, update your employment record in your Personal Tax Account. With two jobs, the allowance goes to the main job and the second gets BR, D0 or D1 — that is normal, not an error.

Scottish and Welsh Prefixes

A code starting with S means Scottish taxpayer: the same £12,570 allowance, but Scottish rates apply — for 2026/27, 19% to £16,537, 20% to £29,526, 21% to £43,662, 42% to £75,000, 45% to £125,140 and 48% above — because the Scottish Government sets its own bands. SD0, SD1 and SK are the Scottish equivalents of D0, D1 and K. A C prefix marks a Welsh taxpayer, who uses the UK rates (20%, 40%, 45%) with Welsh Government control over the rates. Your prefix depends on your main home, not where you work, and HMRC updates it automatically from your address.

Why Codes Go Wrong

Codes drift out of date when HMRC holds stale information: an old job still on record, a company car that ended, benefits not yet reported, or the Marriage Allowance claimed late. A code set too low makes you overpay tax — refunded automatically at year end or by a corrected code; a code set too high makes you underpay, and HMRC recovers the shortfall through next year's code, which is how surprise K codes appear. The HMRC app shows the full breakdown — allowances, adjustments and the resulting number — and lets you challenge anything wrong. For a second income, request a specific split of the allowance between jobs if both pay modestly but the combined total matters.

Marriage Allowance and Other Adjustments

Tax codes carry more than the personal allowance. Claiming the Marriage Allowance transfers £1,260 of allowance and can increase the recipient's code by 126 points, from 1257L to about 1383L, subject to other adjustments. Blind Person's Allowance (£3,250 in 2026/27) lifts an otherwise standard code to roughly 1582L. On the other side, taxable State Pension, company benefits and underpaid tax all reduce the number, and where the deductions exceed the allowance entirely the code turns negative into a K code. The code therefore encodes your whole tax life, not just the basic allowance, which is why a change in circumstances — a pension starting, a benefit ending, a marriage — should prompt you to recheck the code rather than wait for the annual P2 notice.

Reclaiming Overpaid Tax from a Wrong Code

If your code was wrong and you overpaid, HMRC refunds the difference — usually automatically through a revised code or a cheque after the year end — but you may need to nudge it. Check your P60 against your payslips: total tax deducted versus what your income should have produced. If the mismatch is clear, update your Personal Tax Account with the correct figures or call the income tax helpline, and HMRC issues a repayment within a few weeks. Overpayments from more than four years ago cannot be reclaimed, so do not delay. If your code was too high, you owe the difference, and HMRC recovers it through next year's code or a payment plan — a K code appearing after a tax year where you underpaid is the standard mechanism. The lesson is symmetrical: a code checked twice a year is the cheapest insurance against both outcomes. Start the habit at your very first payslip of the tax year — codes rarely fix themselves, and every month a wrong code runs is a month of overpayment or underpayment building up interest in HMRC's favour.

What to keep when challenging a code

Before contacting HMRC, collect the coding notice, latest payslip, P45 or P60, employment start and end dates, pension income and details of any taxable benefit. Write down the code currently used, the code you expected and the fact that appears wrong. If the issue is a company car, medical benefit or State Pension, keep the date it started or ended and the employer or provider notice. This gives HMRC a clear correction rather than a general request to “fix the tax”.

If you have more than one job or pension, list each payer and the code attached to each source. The total allowance may be allocated across sources, so changing one code without checking the others can move the error rather than remove it. For Scottish taxpayers, keep the address and residence evidence relevant to the tax year; the employer's location does not decide the prefix.

After HMRC issues a new code, check the effective date and the next payslip. A cumulative code may recalculate earlier pay, while W1 or M1 continues to work from the current period until the record is corrected. Compare the year-to-date tax, not only the deduction on one payslip. If the annual position remains wrong after the tax year, reconcile the P60 and follow the official repayment or Self Assessment route.

Frequently Asked Questions

Evidence and decision checks

A reliable tax codes explained 2026 27 review starts by fixing the tax year and the date on which the relevant event happened. Record the person's or business's status, the income or transaction category, the amount before tax, tax already withheld, and any election or claim being relied on. Do not combine a headline figure with a final liability: the result can change when another income source, a payment date, an ownership interest or a qualifying condition is added.

Keep the source documents behind every important input. Depending on the subject, that may include payslips, invoices, bank statements, contracts, provider statements, travel records, HMRC notices, payroll submissions, valuations or correspondence. Where an amount is apportioned, write down the method and retain the underlying total. If a correction is made, preserve the original figure and explain the reason, date and evidence for the replacement.

Before relying on the result, check the current official guidance for the same tax year and jurisdiction. Distinguish enacted law from a consultation, draft measure, announcement or future proposal, and record the effective date. Reconcile the final estimate to the relevant return, payroll record or HMRC account. A calculator or explanatory guide can support a decision, but it cannot replace the eligibility test or the official filing and payment process.

Evidence and decision checks

A reliable tax codes explained 2026 27 review starts by fixing the tax year and the date on which the relevant event happened. Record the person's or business's status, the income or transaction category, the amount before tax, tax already withheld, and any election or claim being relied on. Do not combine a headline figure with a final liability: the result can change when another income source, a payment date, an ownership interest or a qualifying condition is added.

Keep the source documents behind every important input. Depending on the subject, that may include payslips, invoices, bank statements, contracts, provider statements, travel records, HMRC notices, payroll submissions, valuations or correspondence. Where an amount is apportioned, write down the method and retain the underlying total. If a correction is made, preserve the original figure and explain the reason, date and evidence for the replacement.

Before relying on the result, check the current official guidance for the same tax year and jurisdiction. Distinguish enacted law from a consultation, draft measure, announcement or future proposal, and record the effective date. Reconcile the final estimate to the relevant return, payroll record or HMRC account. A calculator or explanatory guide can support a decision, but it cannot replace the eligibility test or the official filing and payment process.

Verify your take-home pay against your code with the Salary Calculator→, and read the How Tax Is Calculated guide for the full income tax picture.

Official sources

• HMRC — Tax codes from 6 April 2026
• GOV.UK — What your tax code means
• GOV.UK — Emergency tax codes
• GOV.UK — Income Tax rates and allowances
• Scottish Government — Scottish Income Tax technical factsheet