--- title: Wrong Tax Code? How to Fix It in 2026/27 description: "**Updated for 2026/27.** If your PAYE tax code looks wrong, check the information behind it and correct the source of the error quickly. Employers normally have to use the code HMRC sends, so asking payroll to choose a different code…" url: "https://www.accountingfirms.co.uk/knowledge-bank/what-should-i-do-if-i-think-my-tax-code-is-wrong/" updated: "2026-08-12" category: Income Tax --- # Wrong Tax Code? How to Fix It in 2026/27 **Updated for 2026/27.** If your PAYE tax code looks wrong, check the information behind it and correct the source of the error quickly. Employers normally have to use the code HMRC sends, so asking payroll to choose a different code is rarely the right solution. ## Signs the code may be wrong - An old job or pension is still shown as active - Your full Personal Allowance is attached to the wrong source - A company benefit that ended is still deducted - HMRC's estimated annual income is much too high or low - You are placed on BR, D0, D1 or 0T unexpectedly - A W1, M1 or X emergency marker continues after HMRC has full details - A K code includes income or benefits you do not receive - Marriage Allowance or employment expenses are missing A code can look unusual and still be correct, particularly with multiple jobs, pensions, benefits, tax debt or income above £100,000. ## Step 1: read HMRC's code breakdown Sign in to your Personal Tax Account or HMRC app and open the PAYE/Income Tax section. Check every employer and pension, estimated pay, allowances, benefits, untaxed income and prior-year underpayment. Compare the breakdown with payslips, P45s, benefit information and your latest income forecast. ## Step 2: correct employment and income details Mark an employment as ended where the leaving date is missing, add a genuine source that is absent and update estimated annual pay where the service allows. If a benefit has stopped or changed, tell HMRC the effective date. Keep evidence of the information submitted. ## Step 3: contact the right party Contact the employer when payroll facts are wrong—for example, pay, start date, leaving date, P45 figures or duplicated payments. Contact HMRC when the tax code, income estimate, allowance or benefit adjustment is wrong. An employer cannot normally override a valid HMRC code notice. ## Step 4: obtain and check the replacement code HMRC may issue a new code electronically to the employer and send you a notice. Payroll timing determines which payslip first uses it. Check the code, gross and taxable pay, year-to-date tax and any refund or catch-up deduction. If it remains wrong, compare the new breakdown with the correction you requested. ## Emergency codes A W1, M1 or X marker treats each pay period independently and ignores previous pay and tax. It can prevent an immediate large adjustment but may leave an overpayment or underpayment. Once HMRC has complete information, it may issue a cumulative code that corrects the year-to-date position. ## BR, D0 and D1 codes These tax all pay from one source at basic, higher or additional rate without an allowance. They can be correct for secondary jobs or pensions. Add total expected income from all sources before deciding the code is wrong. ## K codes A K code is used when deductions exceed allowances, often because of taxable benefits, State Pension or unpaid tax. Payroll broadly adds an amount to taxable pay. The deduction resulting from the K code should not exceed 50% of the relevant pre-tax pay for the period. If the underlying items are incorrect, ask HMRC to amend them rather than asking payroll to remove the K. ## Will overpaid tax be refunded through payroll? A cumulative replacement code can produce a refund in a later payslip when sufficient tax was overpaid earlier in the same year. Non-cumulative codes do not usually make that catch-up calculation. After the tax year, HMRC may issue a P800 calculation or the correction may be dealt with through Self Assessment. ## What if too little tax was deducted? HMRC may collect an underpayment through a later code, request direct payment, issue Simple Assessment or include it in Self Assessment. Check the calculation before paying. If an employer failed to operate PAYE correctly, responsibility can depend on the facts and statutory directions; obtain advice where the amount is significant. ## High-income code errors The Personal Allowance reduces by £1 for every £2 of adjusted net income above £100,000 and is normally lost at £125,140. HMRC may restrict the code using estimated income, but pension contributions, Gift Aid, bonuses, savings and dividends can change the final result. A code alone may not settle the liability. ## Example Lewis returns a company car in June 2026, but the estimated benefit remains in his code. He updates the benefit end date through HMRC, which issues a higher cumulative code. His next eligible payroll reduces the year-to-date overpayment. He checks the P60 after 5 April 2027 to confirm the annual result. ## Evidence to keep - Payslips, P45s and P60s - Tax code notices and screenshots of the online breakdown - Benefit start/end dates and employer confirmation - Estimated income calculations - Dates and references for HMRC contact - Any P800, Simple Assessment or Self Assessment calculation Use HMRC's official service to [check current-year Income Tax](https://www.gov.uk/check-income-tax-current-year) and its [tax-code guidance](https://www.gov.uk/tax-codes). First work through our [tax-code checking steps](https://www.accountingfirms.co.uk/knowledge-bank/how-can-i-check-my-tax-code/). ## Frequently asked questions ### Can payroll change the code immediately? Payroll normally needs an HMRC notice, although it can correct its own employee and pay data. ### Will HMRC compensate me for lower take-home pay? Correct tax can be reconciled or refunded, but compensation is not automatic merely because a code estimate was wrong. ### Do I need Self Assessment to fix a code? Not usually for the code alone, but other income or circumstances may independently require a return. *This guide is general information. Seek advice where the underpayment, benefit or employer dispute is material.*