Tax Codes Explained 2026/27: What Your HMRC Tax Code Means

What Is a Tax Code?

A tax code is the instruction HMRC gives your employer or pension provider telling them how much of your pay is tax-free before Income Tax is deducted through PAYE. For most people in 2026/27 the code is 1257L, which means £12,570 of tax-free income spread across the year. The number shows your tax-free allowance divided by ten, and the letter explains your circumstances. If the code is wrong, you pay the wrong amount of tax on every payslip until it is corrected.

You have a separate tax code for each job or pension that pays you through PAYE. Only one of them normally gets your Personal Allowance; the others are usually on a code such as BR or D0. You will find your code on your payslip, your P60, your P45, and in your HMRC personal tax account or the HMRC app.

How a Tax Code Is Built

Almost every code follows the same pattern: a number, a letter, and sometimes a prefix or suffix.

• The number is your tax-free amount for that source of income, divided by ten. 1257 means £12,570. If HMRC reduces your allowance (for example to collect tax on a company car or unpaid tax from a previous year), the number falls. If it increases your allowance (for example for flat-rate job expenses or Marriage Allowance), the number rises.
• The letter describes your situation — see the table below.
• A prefix of S means Scottish income tax rates apply; C means Welsh rates apply. No prefix means the rates for England and Northern Ireland.
• A suffix of W1, M1 or X means the code is being operated on a non-cumulative (emergency) basis.

A worked example: code 1383L means £13,830 of tax-free income — the standard £12,570 plus £1,260 HMRC has added, for example through Marriage Allowance. Code 1150L means £11,500 — HMRC has reduced your allowance by £1,070, often to collect tax on a taxable benefit or on untaxed income.

What the Letters Mean

K codes catch people out. A code of K475 means £4,750 is added to your pay before tax is worked out — typically because of company benefits, State Pension being paid gross, or underpaid tax being collected. Your employer cannot deduct more than half of your pay in tax under a K code in any pay period.

Emergency Tax Codes: W1, M1 and X

If your code ends in W1 (weekly), M1 (monthly) or X, your employer is working out tax on each payslip in isolation, ignoring what you have earned and paid earlier in the tax year. This is called a non-cumulative or emergency basis. It typically happens when you start a new job without a P45, start a new pension, or HMRC has not yet received up-to-date information about you.

Emergency codes do not always mean you are overpaying, but they often do, because you do not get the benefit of any unused allowance from earlier months. Once HMRC updates your record and sends your employer a normal cumulative code, the overpayment is usually refunded through payroll. We cover this in detail in our guide to the 1257L tax code and emergency tax.

The Most Common Codes in Detail

We have written dedicated guides for the codes that generate the most questions from clients:

• 1257L and emergency tax codes — the standard code for 2026/27, and what W1, M1 and X mean.
• BR tax code — why a second job or pension is taxed at 20% from the first pound, and when BR is a mistake.
• 0T tax code — no Personal Allowance at all, why it happens, and how to get your tax back.
• How to claim a tax refund — what to do once a wrong code has left you out of pocket.

How to Check Your Tax Code

The quickest way to check your code is through the HMRC app or your personal tax account on GOV.UK. Both show the code for each employment and pension, how HMRC has calculated it, and the estimated income it is based on. You can also find it on your latest payslip.

When you check, look at three things:

• The estimated income HMRC is using for each job or pension. If it is badly out — for example it still includes a job you left, or overstates your pay — your code may be wrong.
• Any deductions from your allowance: benefits in kind such as a company car or private medical insurance, untaxed interest, State Pension, or underpaid tax from an earlier year. Make sure each one is real and the amount is right.
• Any additions: flat-rate job expenses, professional subscriptions, Marriage Allowance, or relief for higher-rate taxpayers on Gift Aid and personal pension contributions. Make sure nothing you are entitled to is missing.

Our income tax calculator shows roughly what you should be paying on a standard 1257L code, which is a useful sense-check against your payslip.

What to Do If Your Tax Code Is Wrong

Your employer cannot change your tax code on its own — it must use the code HMRC sends. If you think your code is wrong, you need to update HMRC:

1. Update your details online. In the HMRC app or personal tax account you can tell HMRC about a change to your estimated income, a job you have left, a new job, or a benefit that has ended. HMRC usually issues a revised code to your employer.
2. Phone HMRC on the Income Tax helpline if the online service will not let you make the change. Have your National Insurance number, your employer's PAYE reference (on your payslip or P60) and recent payslips to hand.
3. Tell your payroll team that you have contacted HMRC, so they know a new code is coming.

Once the new code arrives, any tax you have overpaid in the current tax year is normally refunded through your next payslip, because most codes are cumulative. Overpayments from earlier years are dealt with separately — see how to claim a tax refund.

If the code is wrong because you have income HMRC does not know about — rental income, self-employment, or large amounts of savings interest — the fix is not to argue the code down, but to report that income correctly. You may need to register for Self Assessment.

Tax Codes If You Have More Than One Job or Pension

HMRC normally gives your full Personal Allowance to your main job or pension and puts the others on BR (20%), D0 (40%) or D1 (45%). This works well if your main job pays more than £12,570. It works badly if your main job pays less than the allowance, because part of your allowance goes unused while your second job is taxed from the first pound.

In that situation you can ask HMRC to split your allowance between the two sources — for example £10,000 against one job and the remaining £2,570 against the other. This is done through the HMRC app, personal tax account, or by phone.

Pensioners often see a reduced code because the State Pension is paid without tax deducted. HMRC collects the tax on it by reducing the allowance given against a private or workplace pension. That is normal and not an error, provided the State Pension figure HMRC is using is correct for the year.

Frequently Asked Questions

What is the normal tax code for 2026/27?

1257L, which gives £12,570 of tax-free income. The Personal Allowance is frozen at this level, so the standard code has not changed for several years.

Why has my tax code changed in the middle of the year?

Usually because HMRC has received new information — a change in pay, a new or ended benefit in kind, a new pension, or underpaid tax from a previous year being collected. Your personal tax account shows how the new code was worked out.

Can my employer change my tax code?

No. Employers must operate the code HMRC sends. The only exception is a new starter without a P45, where the employer chooses a code based on the starter checklist until HMRC issues one.

Does my tax code affect National Insurance?

No. National Insurance is worked out on each pay period separately and is not affected by your tax code.

Get Help With Your Tax Code

Most tax code problems can be fixed in a few minutes online. The difficult cases are the ones involving several jobs, pensions, benefits in kind, or untaxed income, where a wrong code can build up a large bill or refund over several years. Our tax advice team reviews PAYE codes, deals with HMRC on your behalf, and reclaims overpaid tax. Contact us if you would like us to check your code.