Tax Code Checker

What this checker does

Type the tax code from your payslip or from HMRC's notice and the checker decodes it. It shows the tax-free pay the number gives you, how that compares with the standard Personal Allowance, what the letter and any prefix mean, and whether the code is an emergency one. If you also enter your yearly pay, it estimates the Income Tax you would pay under that code over a full year.

What the number means

The numbers in a tax code show how much tax-free income you get in the tax year. You usually multiply the number by 10, so 1257L is £12,570, the standard Personal Allowance. HMRC starts from that allowance, subtracts income you have not paid tax on and other deductions, such as company benefits or the High Income Child Benefit Charge, and replaces the last digit with a letter. A £1,570 medical insurance benefit, for example, turns 1257L into 1100L.

What the letters mean

L means you get the standard Personal Allowance. M means you have received 10% of your spouse or civil partner's allowance through Marriage Allowance, and N means you have transferred 10% of yours to them. T means HMRC needs to review some items with you. 0T means no Personal Allowance is given under this code, either because it has been used up or because your employer has no details for a new job. BR, D0 and D1 tax all the pay from a source at the basic, higher or additional rate, and are normally used for a second job or a pension. NT means no tax is taken.

K codes

A K code is used when deductions for things like company benefits, State Pension or tax owed from earlier years are bigger than your Personal Allowance. The number times 10 is added to your pay before tax is worked out, so you get no tax-free pay. Under a K code, your employer or pension provider cannot take more than half of your pre-tax pay in tax.

S and C prefixes

An S prefix means Scottish tax bands apply and a C prefix means Welsh bands apply, for people whose main home is in Scotland or Wales. This checker decodes both, but estimates tax only with the England and Northern Ireland bands, and does not estimate Scottish codes.

Emergency codes: W1, M1 and X

A code followed by W1, M1 or X is an emergency code. Your tax is worked out only on what you are paid that week or month, as if you earned that amount every period, which can mean the wrong amount of tax. It is usually temporary, for example in a new job. Giving your new employer your P45 is the fix, and HMRC normally updates your code within 35 days of your start date once it has your details. If you have paid too much, you can get a refund.

A worked example

On 1257L with £30,000 of yearly pay, £12,570 is tax-free and £17,430 is taxed at 20%, which is £3,486 a year or £290.50 a month before National Insurance. On K475 with £27,000 of pay, £4,750 is added, so £31,750 is taxed at 20%, which is £6,350 a year.

How to check or correct your code

You can see your current code in your HMRC online account or the HMRC app, on your payslip, or on a tax code notice letter. If it looks wrong, update your details with HMRC. An emergency code that is not corrected lasts until the end of the tax year.

What this checker does not cover

The estimate ignores National Insurance, pay received in several jobs, benefits taxed through the code and the pay-period effect of an emergency basis. It is an estimate, not advice.