A PAYE P6 notice of coding is the electronic instruction HMRC sends to your employer telling them which tax code to apply when working out the Income Tax on your pay or pension. It is not a bill and not a refund. It is a payroll instruction, and once your employer receives it they must update your record before your next pay run. You get your own copy of the same information as a P2 notice, and you can see the underlying calculation any time in your Personal Tax Account.1GOV.UK. Personal Tax Account: Sign In or Set Up For 2026–27, the standard code remains 1257L, reflecting the £12,570 Personal Allowance.
When HMRC Sends a P6
HMRC issues P6 notices electronically through PAYE Online. Employers can also pick them up through the PAYE Desktop Viewer or directly inside compatible payroll software, and HMRC sends an email alert when a new notice is waiting.2GOV.UK. Understanding Your Employees’ Tax Codes: Changes During the Tax Year
There are two typical moments. The first is the annual coding run before 6 April, when HMRC sets everyone’s code for the year ahead. These annual notices are sometimes labelled P9.3GOV.UK. CWG2: Further Guide to PAYE and National Insurance Contributions 2025 to 2026 The second is mid-year, whenever something changes: you start a new job, gain or lose a taxable benefit, claim a tax relief, or HMRC corrects an error from a previous year.
Reading the Code on Your P6
A PAYE code has a number and a letter. Drop the last digit of your tax-free allowance and you get the number: £12,570 becomes 1257. Your employer uses that figure to work out how much of each pay period is tax-free before applying Income Tax to the rest.4GOV.UK. Tax Codes: What Your Tax Code Means
The letter tells the payroll software which rules to follow. The ones you are most likely to see:
- L means the standard Personal Allowance applies. This is the common one.5GOV.UK. Understanding Your Employees’ Tax Codes: What the Letters Mean
- M means you have received a £1,260 Marriage Allowance transfer from your spouse or civil partner.6GOV.UK. Marriage Allowance: How It Works
- N means you have transferred £1,260 of your own allowance the other way.
- T means HMRC needs to review something in your record; tax is still calculated at standard rates.
- BR taxes everything from that job or pension at the basic rate, typically because your allowance is being used at another employment.
- D0 taxes everything at the higher rate for the same kind of reason.
- 0T applies no Personal Allowance, usually because HMRC does not yet have enough information.
Scottish and Welsh Prefixes
If your main home is in Scotland, your code starts with S (for example, S1257L). If it is in Wales, it starts with C. The prefix does not change your allowance. It tells the payroll to apply Scottish or Welsh Income Tax rates, which matters because Scotland’s bands differ from the rest of the UK.5GOV.UK. Understanding Your Employees’ Tax Codes: What the Letters Mean
Emergency Codes
If you start a job before HMRC has sent a P6 and before your P45 arrives, your employer may put you on an emergency code, shown by W1 (weekly), M1 (monthly), or X after the number. Your payslip might display “NONCUM” instead.7GOV.UK. Tax Codes: Emergency Tax Codes These codes are non-cumulative: each pay period is treated in isolation with no reference to what you have earned or paid so far in the year. That often means overpaying tax in the short term. Once a proper P6 arrives, the cumulative code takes over and any excess deducted is refunded through later payslips automatically.
K Codes
Sometimes the adjustments HMRC needs to make add up to more than your entire Personal Allowance. When that happens you get a K code, which works in reverse: instead of shielding income, it adds to your taxable pay. K500 adds £5,000 to what your employer treats as taxable before running the tax calculation.8GOV.UK. Tax Codes: If You Have a K in Your Tax Code There is a safeguard: your employer cannot deduct more than 50% of your gross pay in a single pay period under a K code. Anything above that cap carries forward.
Why Your Allowance Went Up or Down
The number in your code moves because HMRC adds or subtracts items from the standard £12,570. If a mid-year P6 has just landed, one of the following is usually why.
Benefits in Kind
A company car, private medical cover, or an interest-free loan is taxable income even though it never hits your bank account. HMRC estimates the value and reduces your allowance by that amount.9GOV.UK. Taxable Benefits in Kind and Expenses Payments Statistics A £4,000 car benefit turns 1257L into 857L, and your take-home pay drops accordingly.
An Underpayment From a Previous Year
If a past year’s calculation showed you underpaid, HMRC often collects it by shrinking next year’s allowance rather than issuing a bill. This runs automatically when the underpayment is under £3,000 and you earn enough above your allowance to absorb the extra deduction.10GOV.UK. Tax Overpayments and Underpayments: If Your Tax Calculation Letter (P800) Says You Owe Tax The cost is spread across twelve months.
Job Expenses and Reliefs
Professional subscriptions, uniforms, work clothing, and tools bought for your job can qualify for tax relief. Once HMRC accepts a claim, the value is added to your allowance, the number in your code goes up, and less tax is deducted from each payslip.11GOV.UK. Claim Tax Relief for Your Job Expenses: Overview
High Income Child Benefit Charge
If you or your partner claims Child Benefit and either of you earns over £60,000, HMRC can collect the High Income Child Benefit Charge through your code instead of asking you to file a Self Assessment return solely for that purpose. Payment through PAYE must be arranged on or before 31 January in the year after the relevant tax year.12GOV.UK. High Income Child Benefit Charge: Pay the Tax Charge Through PAYE If you already file Self Assessment for other reasons, the charge goes through that route instead.
Untaxed Income and Second Jobs
Rental income, or a pension not taxed at source, is often collected by reducing the allowance on your main employment’s code. The same principle applies when you have more than one PAYE source: your full allowance sits with the main job, and secondary employments or pensions typically carry a BR code so the allowance is not used twice. If neither job pays enough to use up the full allowance, you can ask HMRC to split it between the two employers. The split works cleanly when both incomes are stable; fluctuating hours may leave you slightly out of balance until year end.
How and When Your Employer Applies It
Employers must update the payroll record as soon as reasonably possible and, at the latest, before the next pay run.2GOV.UK. Understanding Your Employees’ Tax Codes: Changes During the Tax Year If a P6 arrives too late in the tax year to use, it is carried forward to the new year.
For a new starter there is a priority rule. If HMRC has already issued a P6 by the time you hand over your P45 or starter checklist, your employer must use the HMRC code, not the code on the P45.13GOV.UK. Late P45 or Starter Checklist If no P6 has arrived, they work from the P45 or apply an emergency code until one does.
Because most codes are cumulative, the payroll software recalculates your year-to-date position when the new code goes in. If you were overtaxed on an emergency or outdated code, the correction shows up in the next payslip or two without you having to claim it back.
Checking the Code and Getting It Fixed
A wrong code quietly drains or inflates your take-home pay every month. Your Personal Tax Account is the fastest way to check: it shows exactly which benefits, deductions, and estimated incomes HMRC has factored into your code.1GOV.UK. Personal Tax Account: Sign In or Set Up
If something looks wrong, you can update the details in the account, use HMRC’s webchat, or call the Income Tax helpline on 0300 200 3300. Have your National Insurance number to hand, plus anything backing up the change you want made: benefit values, expense receipts, a P11D from your employer, or details of income HMRC seems to have estimated incorrectly.
Once HMRC agrees, they issue a fresh P6 to your employer, the code changes on your next pay run, and the cumulative calculation squares up the year-to-date figures for you.
If the Code Was Still Wrong at Year End
After the tax year closes, HMRC reconciles what you actually earned against what was deducted through PAYE. Any mismatch produces a P800 tax calculation letter telling you whether you overpaid or underpaid. An underpayment under £3,000 is normally collected by reducing next year’s code, which is itself communicated to your employer through another P6.10GOV.UK. Tax Overpayments and Underpayments: If Your Tax Calculation Letter (P800) Says You Owe Tax So the cycle closes where it started: with an instruction to payroll, and a change to the number on your payslip.