What is a tax code?

You’ll be able to see your tax code on your payslip – usually near your National Insurance number. The code determines the amount of PAYE (Pay As You Earn) tax you’re charged on your salary – having the wrong tax code, therefore, means you could end up paying too much tax.

This system sees tax deducted directly from your earnings or company/private pension before you receive the money.

This guide explains how tax codes work, lists what the tax code letters mean and what to do if you think you’ve been given the wrong code.

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List of tax codes and what they mean

Find out what the letters in your tax code signify and how your tax will be worked out.

Checking your tax code

Your tax code is assigned by HMRC – it then tells your employer or pension provider which code to use to collect the right tax.

A tax code is usually shown on your payslip, alongside your pay or pension information. It will also be on the coding notice you might receive from HMRC, the P60 you get after the end of the tax year and the P45 if you change jobs.

Every tax code is made up of letters and numbers.

The number 1257, for example, should reflect how much tax-free pay you’re allowed to earn in each tax year – as a general guide, you need to multiply the number by 10 to get the total amount of income you can earn each year before being taxed.

The personal allowance for 2022-23 is £12,570, so the number for many employees is 1257.

The tax code letter gives your employer further information on the type of allowances you receive or the rate of tax that should be charged.

Find out more: tax-free income and allowances – how much you can earn before paying tax

What if you have the wrong tax code?

If you think your tax code could be wrong, you should contact HMRC.

The onus is on you to make sure your tax code is correct. If you’ve overpaid your tax, HMRC will inform you of a refund by post.

You’ll generally be paid back through a tax code adjustment – meaning you’ll pay less tax and therefore receive more of your wages. But if the refund is for a previous tax year, you’ll be sent a cheque.

In the situation where you’ve underpaid tax, you’ll probably have to pay it back. This could either be done by putting you on an emergency tax code, or by issuing you with a tax bill.

Find out more: Income tax calculator – check how much tax you’re meant to pay

Why did your tax code change?

There are a few reasons why HMRC might change your tax code. These include:

  • Starting a new job when your new employer doesn’t have a P45: this will trigger an emergency tax code, as there is not enough information to see how much you’ve earned and how much tax you’ve already paid during the tax year.
  • Receiving an income from an additional job or pension: if your first job uses up your personal allowance, your second income might be taxed on a different code
  • Changing your income: earning more or less can affect how much tax you’re liable to pay.
  • Starting or stopping benefits from your job: this could affect how much money you receive in your payslip, therefore changing how much tax you need to pay.
  • Starting or stopping taxable state benefits, including the state pension, widow’s pension, widowed parent’s allowance, bereavement allowance, incapacity benefit, employment and support allowance and carer’s allowance.

If you’ve been put on an emergency tax code, HMRC will adjust it once it has enough information to do so. You’ll receive a coding notice to tell you when your tax code has been updated.

Find out more: emergency tax codes – what they are, what they mean and what to do if you’re paying the wrong amount.

How to change my tax code

If you think your tax code is wrong, you can inform HMRC by either using its ‘check your income tax‘ online service – where you can update your employment information and tell HMRC about a change in income that may have affected your tax code – or by contacting HMRC directly.

HMRC will contact you if your tax code is changed, as well as notifying your employer or pension provider. You should be able to see your new tax code on your next payslip.

What is a PAYE coding notice?

When your tax code is updated, you will sometimes receive a PAYE coding notice in the post from HMRC.

This details the allowances and deductions you are entitled to and which were used to work out your tax code.

You need to check these details carefully, as incorrect information could mean you’re paying the incorrect amount of tax.

Coding notices are usually sent out in January and February, so any changes can be put into effect by the beginning of the new tax year in April. But you may receive a coding notice at another time of the year if the tax rules or your circumstances change.

You may not get a coding notice at all – if the letter in your tax code is L, P, V or Y, your employer can often just alter your code automatically.

If you think your coding notice is wrong, tell HMRC. You can fill out the online form, or call 0300 200 3300.

What if I have more than one tax code?

You’ll have more than one tax code if you have more than one job or pension.

Your personal allowance will be factored into whichever income HMRC considers to be your main income source. You’ll have to make a request to HMRC if you want your personal allowance to be moved to a different job or pension.

You may find that whoever pays your second income is instructed to deduct tax at the basic rate (20%) or higher rater (40%), using the BR or DO code respectively, if you’ve already used up your personal allowance on your first job. This means you’ll pay tax on all of the money you receive.

How do tax-free allowances affect my tax code?

Tax-free allowances can affect the amount of income you receive, and therefore how much tax you have to pay.

These can include:

  • Personal allowance
  • Blind person’s allowance
  • Pension contributions
  • Gifts to charity
  • Interest payments on qualifying loans

Find out more: tax reliefs – read about the kinds of payments that can reduce the amount of tax you pay through your income.

Work expenses and your tax code

If you pay certain expenses to enable you to do your job, HMRC may also include these in the allowances and reliefs in your tax code.

You can only claim relief on things that are used just for your work, and which you don’t use in your private life.

You can’t claim for things you’ve spent money on if your employer has provided you with an alternative.

You can claim within four years of the end of the tax year in which you spent the money, but you have to keep records and receipts.

If your employer pays back your expenses, you can’t claim tax relief.

For claims up to £2,500, you can fill in a self-assessment tax return, or use form P87. You’ll usually receive money back through adjustments to your tax code, in either the current tax year or the next one.

For claims over £2,500, you can only claim using a self-assessment tax return. If you don’t usually fill one in, you’ll have to register with HMRC first. You’ll receive tax relief through your tax code for the current and next tax years.

  • Get a head start on your 2022-23 tax return with the Which? tax calculator. Tot up your tax bill, get tips on where to save and submit your return direct to HMRC with Which?.

Fringe benefits and your tax code

Your tax code may be used to collect tax on fringe (non-cash) benefits from your employment, such as a company car, accommodation, loans or medical insurance.

These benefits are deducted from your allowances and give you the amount of tax-free pay you are entitled to in a tax year. Your tax code may also be used to collect other tax due – for example, tax that you may have underpaid in previous years or higher-rate tax on savings.

Your employer should give you a copy of your form P11D for your records. You must keep these details for two years after the tax year they relate to.

Tell HMRC if you start or stop getting benefits through your work, as you may be entitled to a new code.


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