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Tax Codes 2017: Check and Update

This guide explains what tax codes are and how employers work them out. Check what you should do any time you think the tax code is wrong.

TAX CODE CHECKER HMRC: How do I tell if my tax code is correct?

Your employer or your pension provider calculates the tax codes. They use a tax code to work out an amount of Income Tax to deduct from your pay or from your pension.

HM Revenue and Customs inform them which code to use so they collect the correct amount from you. GOV.UK has an online facility for checking Income Tax online for the current year. It will show you:

Tax Code Meaning UK

In most cases, tax codes begin with a number and they end with a letter. Most people who only have one job or pension will currently get the 1150L tax code. So, how is this number worked out?

The meaning of the numbers in a tax code is the important part. The tax code numbers give specific information to employers and to pension providers. That enables them to calculate how much tax-free income you can get in each tax year.

  1. The first step takes place by HM Revenue and Customs. They work out how much tax-free Personal Allowance you have.
  2. Any extra income that you did not pay tax on then gets added up. It includes any untaxed interest or part-time earnings. In some cases it will also include the value of any tax on company benefits (e.g. a company car).
  3. Any income that you have not paid tax on gets deducted from your Personal Allowance. The amount remaining is the tax-free income allowed in that current tax year.
  4. The final step removes the last digit in the tax-free income amount.

Tax Code Letter Meaning

Note: The tax codes letters refer to each separate situation. The letter also affects the Personal Allowance for each individual.

Tax Code W1 Meaning (or M1) at the End

Tax codes 'W1' or 'M1' signify that they are emergency tax codes.

Tax Code K Meaning

Some people will see a letter 'K' at the beginning. It means you have income that is not getting taxed another way. In this case it would be worth more than the tax-free allowance. As a rule, this happens most when:

  1. You are paying tax owed from a previous year through salary or through a pension.
  2. You are getting benefits that you need to pay tax on. They can include state benefits as well as company benefits.

Special rules apply to these situations. In these cases it will be your employer or pension provider who takes any tax due. It relates to income not taxed from your wages or pension. This applies even if a different organisation pays the untaxed income to you.

Note: If you are on a K tax code your employer or your pension provider cannot take more than half your pre-tax wages or pension.

Emergency Tax Codes 2017/18

Tax Codes for Income TaxThere are three main emergency tax codes used in the United Kingdom. The payslip of anyone on an emergency tax code will display either:

Being on an emergency tax rate means you pay a levy on all your income above the basic Personal Allowance. This might happen if you start:

Note: The amount of time you spend on emergency tax codes is a temporary process. You can get help updating a tax code from your employer.

How to Get Tax Code Update

Changing your job means you may get put on an emergency tax code. But, it gets corrected by HM Revenue and Customs. The automatic process takes place after you give some details to your new employer. They will need information about your previous income or pension.

Employers get the information from a P45. But they will ask you to provide the details if you do not have your P45.

There are several other reasons why HM Revenue and Customs update tax codes. It can occur any time you:

Tax Code Change

The tax code adjustment made by HMRC means you pay the right amount across the year. HM Revenue and Customs will send you a letter or email once they complete the update.

HMRC also inform your employer or pension provider of the changes. Thus, when you get your next payslip you should see:

Informing HMRC of Change of Tax Code

There are several steps you can take if you think the coding is wrong:

  1. Use the online tool to check your Income Tax and inform HMRC of any changes to your circumstances.
  2. You can also contact HM Revenue and Customs if you are unable to use the online service.

Contacting HMRC for Someone Else

There may be times to inform HMRC of a change in circumstances for someone else. A typical example would be if you are their appointed tax agent or accountant. In this case, fill in a PAYE Coding Notice query form and state the changes.

Income Tax Code Meaning as used in the United Kingdom