Free Tax Code Calculator
Check if you're owed a rebate
It looks like an innocuous set of digits, but your tax code can have a big impact on your finances. Every year, millions of people are hit by errors – and some are due £1,000s back. So do a quick check with our Tax Code Calculator to see if your code's right. If it's wrong, read on to see how to deal with underpaid or overpaid tax.
Use this summary and the links to our calculator if you know what you're doing. Alternatively, read our full guide below for detailed help.
Know your tax code? If so, head straight to our Tax Code Calculator.
Don't know your tax code? Here's how to find it – though if you have one employer and earn under £100,000, it's likely to be 1257L (with an S at the start if you live in Scotland and a C at the start if you live in Wales).
Overpaid (or underpaid) tax? We've full info on your next steps, whether you've underpaid tax and have a bill to pay, or you've overpaid tax and are due a rebate.
Thanks to Tony Tesciuba (Tesciuba Ltd) and Matthew Brown (Chartered Institute of Taxation) for feedback/suggestions. While every effort's been made to ensure accuracy, this guide isn't authorised, tailored tax advice (get help here). We can't take responsibility nor accept liability for damage or losses; you use the info at your own risk.
What is a tax code?
A tax code is simply a series of numbers and letters, for example 1257L, S1257L, C1257L, BR, and K497.
If you're a full or part-time employee, or receive a private pension, these hieroglyphics are used by your employer(s) or pension providers to calculate the amount of tax that should be deducted from your wages or pension before it's paid into your bank account.
This is known as the pay-as-you-earn (PAYE) system, though not everyone is taxed in this way. You won't have a tax code if you're fully self-employed, unemployed or you only receive the state pension.
How do I find my tax code?
Each income you have (jobs, private pensions) will have a different tax code. Remember to check them all. Here are the best places to look for your tax code(s).
Payslip | Ask your employer if you can't locate your latest one. |
PAYE coding notice (or P2) | Sent around January to March, before the start of the tax year. It explains how your code was generated. |
P45 | The form your employer gives you when you stop working for it – and the one you give to your new employer when you change jobs. |
P60 | An annual summary of your salary and the tax that's been deducted. Your employer is required to give you this at the end of each tax year. |
Pension advice slip | If you're receiving a private pension, the easiest place to find your code will be on any pension advice slip or on your P60 sent once a year. |
HM Revenue & Customs (HMRC) | You can check your tax code with HMRC online or by using its app – read our full guide to the HMRC app. |
Keep reading: What your tax code means »
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