
Free Tax Code Calculator
Check if you're owed a tax rebate
It looks like an innocuous set of digits, but your tax code can have a big impact on your finances. Every year, many people are hit by errors – and some are due £1,000s back. Use our Tax Code Calculator to check you're on the right tax code, and read our guide for how to handle underpaid and overpaid tax.
Do you know your tax code? If so, head straight to the Tax Code Calculator. If not, here's how to find it - though if you have one employer and earn under £100,000, it should be 1250L.
The Tax Code Calculator

If you already know your tax code, use our calculator below to get a ROUGH idea of whether it's correct (it's impossible to be exact). If it seems wrong, it could be worth taking action to check whether you're owed (or owe) cash.
Got one employer, no work perks, live in England/NI and earn under £100,000? Your 2020/21 code should be 1250L.
If you've been furloughed or you've been made redundant from a job due to coronavirus, we've added some help to guide who might need to check their tax code because of this.
What is a tax code?
On the face of it, a tax code is a dull and harmless series of numbers and letters – 1250L, S1250L, C1250L, BR and K497 are just some examples for the current tax year.
But these hieroglyphics are used by your employer to calculate the amount of tax that should be deducted from your wages or pension before they hit your bank account.
Therefore if you pay tax through the pay-as-you-earn (PAYE) system, the tax code tells your employer or pension provider what it should take – and even small errors can lead to mistakes of £100s.
So the aim here is to find your tax code and decipher what it means, to see if it's correct. But it's worth knowing that not everyone has a tax code.
Who has a tax code?
Full or part-time employees
Those receiving a private pension
Who doesn't?
Fully self-employed or unemployed people
Those ONLY receiving a state pension
Taking on your tax code is not an appealing task for even the most dedicated MoneySavers. But it doesn't have to be that gruelling. The most important thing to remember is...
Each income you have (jobs, private pensions) will have different tax codes. Remember to check them all!
Here are the best places to look for your tax code...
- Your payslip. Perhaps the easiest place to look is on your payslip, which you'll receive from your employer every time you get paid.
- Your PAYE coding notice (or P2). It's sent to you around March, just before the start of the tax year. It explains to you how this code was generated.
- Your P45. This is 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.
- Your P60. This is 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.
- HMRC. If you can't lay your hands on any of these, you can check your tax code with HMRC online. You'll need to create an account or sign in with your Government Gateway/Gov.uk Verify ID if you already have one.

What your tax code means
Tax codes are made up of two main elements, which determine the amount of tax your employer will take. If you work for multiple employers (or work and also draw a pension), you'll have more than one code.
Your tax code will usually be made up of letters and numbers. Here's an example of a common tax code for the current tax year (similar ones for past years include 1185L and 1150L):
The letters and numbers indicate different things...
- The numbers. These three or four digits indicate what your tax-free allowance is – that's the amount you can earn in a year before your employer needs to deduct tax. The size of this allowance depends on your income and whether there are any deductions (eg, company car) or additions (eg, pension contributions) to this.
You need to add a zero to get the real number, so 1250 means you can earn £12,500 a year tax-free. This is called your personal allowance. Above that, you pay tax on income, though the amount you pay depends on your total earnings (see current tax rates).
- The letter(s). This may relate to a number of different factors, and you should use the Tax Code Calculator to check that the definitions are relevant for you.
It usually refers to your age, at what rate employment is being taxed and whether you have any unusual circumstances. The most common letter is L, but those who live in Scotland will see an S at the start, and those in Wales a C.
Others may see a BR code – this is most common for second jobs, or pensions. But there are lots of different letters and combinations of letters, so use the calculator to see what they all mean (and check that they should apply to you).
How to find what your tax code should be
First, check the number's correct. HM Revenue & Customs works it out like this:
Your personal allowance – any deductions = number in your tax code
If you have benefits at work, you may have some deductions. Common ones include discounted rent or household bills, vehicle use, medical insurance, healthcare cash plans, some travel costs, payment in vouchers, and goods bought on company credit cards.
These deductions are subtracted from the total amount of tax allowances you get (probably your basic personal income tax allowance), and what's left is the total amount of tax-free income you are permitted in each tax year.
HMRC then removes the last digit of this number (so 1250 in the case of the 2020/21 standard £12,500 personal allowance) – and hey presto, you've established the number part of your tax code.
In the majority of cases, these numbers will be followed by a letter. And this letter will vary according to your particular circumstances, so it's important to check the letter's correct too.
If your code's not 1250L, check if any of the following apply...
The HMRC slogan that "tax doesn't have to be taxing" is well intentioned, but rarely true. If your code's not the standard 1250L, click on any of the following statements that apply to you – it may explain any discrepancies in the code. There's lots of extra info on Gov.uk too.
How coronavirus income changes could affect your tax code
It's an unsettling time for many, and the coronavirus crisis means changes to our work, whether that's being furloughed and potentially adapting to a lower salary, having to stop work as you can't run your business or being made redundant from your job.
Whether these changes are something you need to let HMRC know about, or mean you need to keep an eye on your tax code or the amount of tax you're paying will depend on your circumstances.
Got one job and earn less than £100,000? It's unlikely your tax code will change, but worth checking
For the vast majority who are on a version of the 1250L tax code (S1250L in Scotland, C1250L in Wales), if you're put on furlough, it'll likely just mean a change in the amount of money you have coming in. It's unlikely to have an effect on your personal income tax allowance (£12,500 for most), and it's that that helps dictate your tax code.
We've spoken to HMRC, which advises that you don't need to contact it if you've been furloughed or otherwise had your income affected. It'll know about changes to your income or employment from your (old) employer, or through self-assessment.
It also says if you're now paying too much or too little tax due to a change in circumstances, this will usually be corrected during the tax year (tax information is now submitted in real time, rather than checked at the end of the tax year).
But if you've not checked your tax code in years, it's worth checking it now using the calculator above, in case you've been on the wrong code for a long time and just not realised.
Got more than one source of income, or earn £100,000+? It's definitely worth checking
There are a few sets of people who should keep an eye on their tax code (and the amount of tax they pay) this tax year, as coronavirus could have some consequences. See if you might be affected...
What to do if your tax code's wrong
Now you understand what your tax code means, you'll be able to assess whether it's likely to be correct for your earnings, age and situation. If your tax code doesn't look right, it probably isn't.
The onus is on you to get on the right tax code. We now have two possible scenarios, and one is much more fun than the other. If you've overpaid tax, read on. If you've underpaid, skip to the "I've underpaid" tax help.
It's probably simplest to call HMRC on 0300 200 3300 so you can resolve your situation with a human and ask questions along the way. Alternatively, you can contact HMRC online via your personal tax account to let it know your tax code is wrong – you'll need to log in/set up an account using your Government Gateway or Gov.uk Verify ID.
Here's some inspiration from a MoneySaver who queried the amount of tax they were paying...
I want to thank you - you recently stressed the importance of checking your tax code. After I was recently made redundant, I got my P45 and phoned HMRC. I said: 'Look, can you just check this for me?' They checked a couple of things, said: 'Can you stay on the line?', then said: 'We owe you £11,486 – how would you like it paid?' The cheque arrived 10 days later.
I had just trusted the amount of money HMRC had taken off my redundancy pay – then my instinct kicked in after your warnings. This success has allowed us to clear our debts and plan for the future.
Tina, via email
Please report successes/failures getting money back in the Tax Code Calculator successes forum discussion.

How and when will I be repaid?
This depends on the tax year your claim refers to. If it's the current tax year and you're paying too much tax as a result of your tax code right now, HMRC will inform your employer, the tax code will be amended and the overdue tax will be refunded to you via your wages.
After the end of the tax year, HMRC will send you a P800 (or in some cases a 'simple assessment' letter). If you're self-employed or if the tax refund refers to previous tax years, you'll be able to claim your refund online (your P800 will tell you if you can) or HMRC will send a cheque in the post.
In some cases, HMRC will pay a paltry rate of interest on any tax you have overpaid – since September 2009, you earn 0.5% on overpaid tax.
How far back can I claim?
You can claim back up to four years of overpaid tax, if the problem's been going on that long. The deadline for claiming back overpaid tax in the 2016/17 tax year is 5 April 2021.
However, even if the deadline has passed for the tax year in question, don't let this put you off getting back what's yours. In certain circumstances – including when HMRC is at fault – your claim will be considered. So fight your corner.
Quick questions
In most cases, you'll have to pay it back – generally HMRC can only go back four tax years, but this extends to six if you acted carelessly and 20 if you acted deliberately.
How you go about paying what you owe depends on the amounts involved and how HMRC has dealt with your case – though it's always important to check you agree with HMRC about how much tax you've underpaid.
But it wasn't my fault I'm on the wrong code!
The official line from HMRC is that it is each individual's responsibility to check they are on the right tax code.
However, if your code was wrong there are some situations where you might not have to pay the tax bill. This could include:
- If your employer made a mistake and put you on the wrong tax code despite being sent the correct one by HMRC. In that case, HMRC should try first to recover the tax from your employer.
- If HMRC reviews your tax and finds an underpayment of £50 or less in the last year, it'll write off the tax.
- If the underpayment was made in a tax year ending more than a year ago, you may be able to challenge via the not-so-catchy name of an extra-statutory concession – or an A19 (read more about this on Gov.uk and below).
See the Low Incomes Tax Reform Group's guides on underpaid tax for more.
How to reject underpayments more than a year old
Using an A19 – a little-known clause which lurks deep in HMRC's complex book of rules – ISN'T guaranteed, and in fact it's far from likely to work. But there is a possibility, so it may be worth giving it a go.
A19 doesn't apply to me – I have to repay. How do I do that?
If you do owe the tax HMRC claims you do, you will have to repay. But the good thing is you don't have to repay it all at once. For smaller amounts, you can pay through your tax code over the next year. And for larger amounts, you can agree a repayment plan with HMRC.
Quick questions
Keep an eye on future codes
With any luck, once you have established the right tax code, it'll all be sorted with HMRC from then on, unravelling the web of complexity surrounding tax codes and what you ultimately should be paying. Yet don't bank on it...
Small changes can change your code
Every time your circumstances change – whether it's a promotion at work with a larger salary, new employee benefits, taking on another job, giving up work to have children or leaving the country and the UK tax system altogether – your tax code may change, so it can be worth getting in touch with HMRC to establish your new tax code.
Updating your details today can save an awful lot of hassle and expense in future. You can update these details (and others, such as your address) through your Gov.uk personal tax account.
Get free tax help
This guide provides general information about tax codes to help you see if you're on the right track. But it's no substitute for personal advice if you need it – and you should always take care to ensure you're definite about any actions you're taking.
The following organisations all give help and advice, and some don't charge a fee, so give them a try if you're struggling:
Tax Aid: Lots of info is available here, but TaxAid can only help those on a low income who can't resolve their own issues with HMRC.
Citizens Advice: Visit Citizens Advice's website to get the number of your local Citizens Advice bureau.
Low Incomes Tax Reform Group: This is an initiative from the Chartered Institute of Taxation, aimed at those with low incomes who have tax problems. Visit LITRG.
Tax Help for Older People: If aged over 60, you can try Tax Help for Older People online or by calling 01308 488066.
Find a tax adviser: If you can afford it and have more complex affairs, you can use the Chartered Institute of Taxation's 'Find a Tax Adviser' search.
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