Free Tax Code Calculator

Find if you're owed a tax rebate

It looks like an innocuous set of digits, but your tax code has a critical impact on your finances. Every year millions of people are hit by errors, and some are due £1,000s back. Letters with your 2017/18 code were sent in the summer so if you haven't already, check yours NOW.

This guide includes the Tax Code Calculator, updated for the 2018/19 tax year, to ensure you're on the right tax code, and how to handle underpaid and overpaid tax. It's likely millions each year still could be owed (or owe) £100s.

In this guide

Thanks to Tony Tesciuba (Tesciuba Ltd) & Matthew Brown (Chartered Inst of Taxation) for feedback/suggestions. Every effort's been made to ensure accuracy, yet 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's a tax code?

Before we start explaining what a tax code is, it's important to understand that not everyone has one.

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

On the face of it, a tax code is a dull and harmless series of numbers and letters – 1185L, S1185L, 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 PAYE, 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. Don't worry, we'll take you through it simply.

Then you can punch it into our unique tax code calculator which will give you a steer on whether you may have over- or underpaid. Finally, and most importantly, the guide will explain step-by-step what to do about it...

Quick questions

  • In summer 2010, errors started coming to light and, so far, OVER 30 MILLION mistakes for tax years between 2003/04 and 2015/16 have been uncovered by HMRC.

    People pay the wrong amount of tax often because they've changed jobs midway through the tax year, or they've retired, or some other change.

    Commentators often point the finger at HMRC, though many tax nerds dispute this, saying its reconciliation – that it does at the end of each year – reveals errors, it didn't create them. Current employers can only use the tax code they are told to; the key is having correct info flowing through the system.

  • The errors are indiscriminate but some groups of people are likely to be more affected than others. You should take action quickly if one of the following situations has applied to you in the recent past.

    • Have you changed jobs? The tax system can incorrectly assume you have two jobs if your former employer hasn't let HMRC know you've moved on.

    • Do you have more than one income? If you've been earning money from more than one source (eg, you have a second job), then you could find you've been taxed incorrectly on a chunk of your earnings.

    • Do you get employee benefits? If part of your salary is made up of company benefits such as a company car, healthcare cashplan or medical insurance, it's possible you're being taxed wrongly.

    • Just started your first job? Young people embarking on first jobs in the middle of a tax year can easily be shunted on to an emergency tax code. Never assume the amount you receive in the first few pay packets is correct.

    • Do you have more than one pension/have you recently retired? If you receive money from more than one pension source, have retired in the last couple of years or have recently started to receive the state pension, you could have been taxed incorrectly.
  • If you've moved house and not told the taxman, any correspondence from HMRC about your tax code may have gone to the wrong address. Your employer can't update this, only you can, so if you haven't, a possible refund could've gone to the wrong address.

    You must contact HMRC directly to update your address. The easiest way to do this is online at HMRC's website.

People have used this guide to reclaim up to £10,600!

Since launching this guide in late 2010, we heard of a blast of successes after MoneySavers used the Tax Code Calculator and realised they were on the wrong code! We'll let some lucky forumites take over the tale. Please tell us about your tax rebate successes.

Seeing the email, I thought I'd check mine as I had my payslip handy and I was surprised to see my code was BR. Digging out older slips, I saw I'd been on basic rate tax since I started, which seemed odd.

Quick call to HMRC confirmed I should have been on L – they've refunded just under £1,500 for last year and are updating my employer, so I'll be £130 better off each month going forward!

I got the MSE email, checked my tax code, rang HMRC and it told me I'd get between £5,000 and £7,000 back. Incredible!

It's all because it'd been deducting for a company car and medical insurance that I've never had in this job.

Chris Kendall

I was made redundant last year so was entitled to redundancy, and as part of sorting my finances out etc. I checked my tax code via my accountant and received a whopping £10,640.

I've rung HMRC and a letter is in the post. I've been on the wrong tax code and paying too much since 2005!

I've had a cheque for £3,698 dating back to 2006 and that's not including this year's return either! I'm very happy indeed and would of been none the wiser had it not been for MSE so thank you very, very much!

Step 1. Finding your tax code

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.

How do I find my tax code?

It's listed on your 'coding notice', payslips or P45s. The most important thing to remember...

Each income source (job, private pension) will have different tax codes. Check them all!

The best source to find your tax code is your PAYE Coding Notice (or P2). A copy of this is sent to both you and your employer around March, just before the start of each tax year. It tells them how to deduct tax, and explain to you how this code was arrived at.

If you can't find your coding notice, then there's other places to look for your tax code...

  • Your payslip: Perhaps the easiest place to look is on your payslip, which you will receive from your employer every time you get paid (whether it's monthly or weekly).

  • Your P45: If you have dumped your payslips, (though it's always best to keep them for records) hunt down a copy of your P45. This is the form given to you by your employer when you stop working for them – and the one you give to your new employer when you change jobs.

  • Your P60: This form is a 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.

  • HM Revenue and Customs: If you can't lay your hands on any of these, contact your tax office with your National Insurance number. After a few basic security questions, they will disclose your tax code (or codes) to you.

  • Tax code for pensions: 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.

What does my code mean?

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.

Here's an example of a common tax code for the new tax year in April (similar ones for past years include 1150L and 944L). It will usually be made up of numbers and letters:

  • It indicates the first three or four digits of your tax-free allowance – the amount you can earn in a year before your employer needs to deduct tax. The size of this layer 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 on the end to get the real number, so 1185 means you can earn £11,850 a year tax free. Above that, you pay tax on income, though the amount you pay depends on your total earnings.

    For the 2018/19 tax year (which runs from 6 April 2018 to 5 April 2019):

    • You pay 20% tax... on the portion of your income that is between £1 and £34,500 above your personal allowance. This is called basic-rate tax.

    • You pay 40% tax... on the portion of your income that is between £34,501 above your personal allowance and an overall salary of £150,000. This is called higher-rate tax.

    • You pay 45% tax... on the portion of your income above £150,000. This is called additional-rate tax.

    If you live in Scotland, tax rates are different. For the 2018/19 tax year:

    • You pay 19% tax... on the portion of your income that is between £1 and £2,000 above your personal allowance. This is called starter-rate tax.

    • You pay 20% tax... on the portion of your income that is between £2,001 and £12,150 above your personal allowance. This is called basic-rate tax.

    • You pay 21% tax... on the portion of your income that is between £12,151 and £31,500 above your personal allowance. This is called intermediate-rate tax.

    • You pay 41% tax... on the portion of your income that is between £31,501 above your personal allowance and an overall salary of £150,000. This is called higher-rate tax.

    • You pay 46% tax... on the portion of your income above £150,000. This is called additional-rate tax.
  • 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 that employment is being taxed, and whether you have any unusual circumstances. Here are a few examples:

    • L – most common code – you're eligible for standard personal allowance.

    • BR – whole income taxed at 20% – usually for second jobs/pensions.

    • NT – no tax to be deducted from this income – often used if you live overseas.

What SHOULD your tax code be?

This is where you need to switch on your brain. The key bit to check it's correct is the number...

  • Find your personal allowance

    The first thing that HMRC does to establish your tax code is to tot up all of your tax allowances – in other words how much you can earn before you start to pay tax. In many cases this will be just your personal allowance.

  • Are there any deductions?

    Any income you haven't paid tax on at source is known as your deductions. The usual suspects are taxable employment benefits or extra income, eg, renting out a property or State Pension.

    Common taxable benefits include discounted rent or household bills, vehicle usage, medical insurance, healthcare cashplans, some travel costs, payment in vouchers and goods bought on company credit cards.

  • Use these to make the number in your tax code

    These deductions are subtracted from the total amount of tax allowances you get (probably your basic personal 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 1185 in the case of the 2018/19 standard £11,850 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.

Step 2: The Tax Code Calculator

To try to help you work out whether your code's correct, we've devised an easy-to-use calculator to give a ROUGH answer (it's impossible to be exact). If it seems to be wrong, it shows it could be worth taking action to check out whether you're owed cash (or will be asked to pay back).

Have one employer (& no work perks) and earn under £100,000? Your 2018/19 code should probably be 1185L.

Before using the tax code calculator

HMRC's famous slogan that 'tax doesn't have to be taxing' is well-intentioned but is rarely true. If you don't fit the average working mould, click on the following statements for an explanation of how your situation differs – it may explain any discrepancies in the code. There's lots of extra info on the website too.

  • The amount of tax you pay is based on your total income for the tax year – whether this is from one, two or more jobs, interest on savings or rental income from a second property that you own. But you will still only have one personal allowance (the amount you can earn before tax) for all of them.

    You will be issued with a separate tax code for each job – and these are likely to be different. For example, if your main income does not take you above the basic 20% rate of tax, you may be on a 1185L tax code for your main job and a BR code for your second job.

    Or if you work four days a week in one job and earn £50,000, and have a second job paying £30,000, your tax code could be 1185L for the first job and D0 for the second job because the £30,000 earnings will be taxed entirely at the higher rate of 40%.

    It's important to ensure HMRC knows which is your MAIN job (generally the one that pays you most) as if it's the wrong way round it can cause problems.

    Your PAYE Coding Notice (also known as a P2) should tell you what each tax code is for each job and how it was worked out. If it's unclear, call HMRC to get some answers.

    How to use the calculator with multiple jobs

    • Put each code in the calculator separately, ideally starting with your main job, ie, the one that pays you the most

    • Your overall personal allowance is the sum of allowances from all the tax codes you have. For example, if you had tax codes 300L and 250L, then the tax-free allowance given to you by your tax codes is £5,500

    • Note down all the personal allowances given to you by your tax codes, and add them up. If these aren't equal to the allowance that your age and salary predict for you (the calculator lists this), then it's worth taking things further
  • If you have just left education and are going in to your first job, you should be put on the tax code that reflects your earnings and position. For example, if you qualify for a basic personal allowance of £11,850, you should be put on the standard tax code of 1185L.

    However, a code of BR (with no numbers) or something looking like 1185X, 1185 M1 or 1185 W1 may also be used if you've started a new job, don't have a P45 form and haven't completed a P46 form before your first pay day.

    Sometimes it can take a month or so for HMRC to get you into its system and on the right tax code. But, so long as your P46 has been completed and filed, any tax you have overpaid will come back to you automatically in your next wage packet. If not, you should chase up after the tax year.

  • If you took time out from your job to have a family and are bracing yourself to get back on the working wheel, you should automatically be put on the tax code that reflects your earnings and position. For example, if you qualify for a basic personal allowance of £11,850 you should be put on the standard tax code of 1185L.

    However, a code of BR (with no numbers) or something looking like 1185X, 1185 M1 or 1185 W1 may also be used if you've started a new job and haven't completed a P46 form before your first pay day. Even if you can lay your hands on it, your last P45 won't be any good to you now as it is only valid for the current tax year.

  • If you have been working overseas and paying tax to a different country, you should be put on the tax code that reflects your new earnings and position as soon as you return to the UK and start working again. For example, if you qualify for a basic personal allowance of £11,850, you should be put on the standard tax code of 1185L.

    However, a straightforward code of BR (with no numbers) or something looking like 1185X, 1185 M1 or 1185 W1 may also be used if you've started a new job, do not have a P45 form (which should have been given to you by your last employer) and haven't completed a P46 before your first pay day.

    However, if there are still tax issues hanging over from the country you had previously been working in, you may find you are put on a T code, which indicates that your tax position is not settled and will need to be reviewed regularly by HMRC.

  • This is where things can get complicated. The letter after your numbers – which will be your total personal allowance with the last digit removed – could be either an L or a T.

    Which it is depends on the value of the taxable benefits, such as company car, dental care, private health care, mobile phone, vouchers or laptop.

    If you're a higher rate payer (earning more than £34,500 (more than £31,580 in Scotland) above your personal allowance in 2018/19) or an additional rate tax payer (earning over £150,000) and have the perks to match, you are likely to be on the T code, denoting that your tax affairs need regular review.

  • Claiming either of these WON'T make any difference to your tax code.

    Working tax credits are classified as a 'means-tested' benefit so this is not deducted from your individual personal allowance. However, while it's not part of your tax situation, if your circumstances change and you earn a higher salary for example, you will need to inform the Tax Credits office and this may affect your entitlement. See the full Tax Credits guide.

    Child benefit was withdrawn from some higher earners in January 2013, with people earning between £50,000 and £60,000 a year only remaining eligible for a portion of it, and those earning £60,000 or above not eligible at all.

    If this is you, you can still claim the child benefit, though it must be repaid at the end of the year. You can also choose to pay through your tax code, which will lower your personal allowance. You'll also have to fill in a self-assessment tax form.

  • If you are eligible for the full personal allowance (£11,500 in 2017/18) and were born between 6 April 1938 and 5 April 1948, you used to have a boosted allowance, and thus the letter P used to be tagged at the end of the numbers in your tax code. However, as the personal allowance for everyone is now £11,850, it's likely your personal allowance will be 1185L.

    If you were born before 6 April 1938 you used to also have a boosted personal allowance (of £10,660 for this age bracket in 2015/16), and the letter Y would be tagged at the end of the numbers in your tax code. However, as the personal allowance for everyone is now £11,850, it's likely your personal allowance will be 1185L.

    Income from state pensions will also be subtracted from your personal allowance. If your total taxable deductions exceed the personal allowance available you will have a negative coding – where a K is used.

Step 3: Think your tax code's wrong?

Now you understand what your tax code means, you will 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!

But, don't panic...

  • If you have overpaid tax, the money will come back to you.
  • And if you have underpaid, not only do debtors' prisons no longer exist, you probably won't have to pay it back all in one go either.
  • If your tax code is wrong...

    The first thing to do is get in touch with HMRC. Tell them you think your tax code may be wrong and why.

    It's probably simplest to call HMRC so you can resolve your situation with a human and ask questions along the way. You can call it on 0300 200 3300 or you can fill in an online form on the HMRC website to let it know your tax code is wrong.

    If HMRC agrees you've overpaid tax it will only ever inform you of a refund by post. This is a crucial point to remember following a spate of clever email and phone scams, so never discuss this with anyone over the phone, or via email.

    Therefore usually it simply means identifying the overpayment and informing HMRC is the key way to get any overpaid cash back.

    How and when will I be repaid?

    This depends on the tax year your claim refers to. If it is the current tax year and you are 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.

    If the tax refund refers to previous tax years, you'll be sent a refund by cheque in the post. You can opt to be repaid by BACS transfer but in this case you will need to supply your bank details by letter as, for security reasons HMRC will not accept bank details over the phone.

    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 (the year before it was 0%).

    How far back can I claim?

    You can claim back up to four years overpaid tax, if the problem's been going on that long. Here are all the time limits for claiming a refund:

    Tax year (ends 5 April)

    Deadline for claiming


    5 April 2019


    5 April 2020


    5 April 2021


    5 April 2022


    5 April 2023

    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.

  • In most cases you'll have to pay it back – and unlike when you have overpaid there is NO limit on how far back the taxman can go back.

    How you go about paying what you owe depends on the amounts involved and how HMRC has dealt with your case.

    But it wasn't my fault I am on the wrong code!

    That doesn't matter. We may have done away with debtor's prison, but the state wants its cash as much as ever. This means that even if you are on the wrong tax code through no fault of your own, the same procedures will apply as if it was your fault.

    The official line from HMRC is that it is each individual's responsibility to you check they are on the right tax code, so mistakes made by former employers are technically your problem.

    However in light of the recent massive publicity over the huge number of people who have been in the wrong code, some limited concessions have been made, such as writing off underpayments of £50 or less in the last year.

    Is the underpayment more than a year old? You may be able to reject it...

    The one potential hope to challenge goes by the not-so-catchy name of an Extra Statutory Concession – or an A19 (read about this on HMRC website). However, HMRC is looking to make it much harder to claim using the A19 concession – more below

    It's a little-known clause that lurks deep in HMRC's complex book of rules stating that..

    If the taxman failed to inform you of underpayment within 12 months of the tax year's end, your debt COULD be written off.

    This ISN'T guaranteed, and in fact it's far from likely it will work. But there is a possibility, so it may be worth giving it a go.

    To even think about going down this route, you must strictly fulfil the following criteria:

    • The overpayment is more than 12 months old.

    • HMRC was given the CORRECT information (which is purely on the onus of you and your employer but if you're one of the 'mistake' cases that's likely).

    • Lastly, you will need to genuinely demonstrate a 'reasonable belief' that your tax affairs were in order which can become pretty tricky – if you suddenly started receiving loads more pay, it can be argued you should have spotted it!

    This means that at present, if you underpaid in the 2015/16 tax year or earlier you may be able to go the A19 route (from 6 April 2018, you'll be able to claim for the 2016/17 tax year too).

    You will also need to have all your paperwork and dates in perfect order.

    However, if you feel as though injustice has been done and, as a result, you can overcome these hurdles and apply for exemption under an A19 simply by calling or writing to HMRC.

    Download a template letter

    With thanks to the Low Income Tax Reform Group

    This is definitely worth a go if you qualify, we've an A19 full how to, though remember it's far from a sure thing. But, we have received emails telling us of successes – one reader had a £1,700 repayment written off after HMRC didn't follow procedures properly.

    I am delighted to tell you that my underpayment (£1,700) has been written off under the A19 ruling. The underpayment HMRC had already started deducting from my pension has been refunded.

    Changes to the A19 concession

    HM Revenue & Customs proposes to change the A19 concession to make it harder to claim. The main change will be a change in emphasis, making you (not it) responsible for checking your tax code to make sure it's correct – if you've not done this, your appeal won't be upheld.

    Reports from tax advisers using the A19 concession for clients tell that claims which would have been approved by HMRC in previous years are being rejected – mainly on the "reasonable belief" criterion – did the taxpayer check their coding notice, and that it was a true reflection of their circumstances?

    It's doubly important now to make sure any claim is watertight, and also to go in with little hope of a good outcome – the previous 1 in 4 success rate is unlikely to be achieved now – especially if you can't prove that you checked your tax code when sent it, and notified HMRC of any errors at that point.

    In any case, ESC A19 may have a limited shelf life. HMRC reconciles all cases of complicated tax affairs at the end of every tax year – meaning that it's very unlikely that more than a handful of cases will receive notification of underpaid tax more than a year old.

    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, then you will have to repay it. But the good thing is that 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. We've answered some common questions about tax underpayment here:

    Quick questions

    • When HMRC began sending out letters asking for multiple years' worth of old underpayments back it confirmed that if you owed less than £300, the 'debt' would be written off; great news! On top of this, any underpayments requested for the tax year immediately previous won't be requested if they are under £50 (you likely won't even be aware of this, as HMRC won't contact you if you owe less than £50).

      But not so good is the statistic that the average underpayment is around £1,400, meaning a big bill for many.

      The good news is, you won't have to pay all this back in one go – you can call HMRC and arrange a payment plan instead. There is only one kind of payment plan in this case, which involves taking instalments at source from your earnings through your tax code.

      And you'd better brace yourself because this will mean your tax code will have to be altered accordingly – meaning higher bills in future years.

    • That will depend on the amount you owe...

      • If you owe less than £3,000:

        HMRC may simply adjust your tax code at the start of the new tax year to claw back the sum you owe. For example, if you had underpaid £300 during the last tax year, you would need to be taxed on an additional £1,500 of income (if you paid basic rate tax of 20%) over the next tax year to repay this sum.

        This means that £1,500 would need to come off your personal allowance for the next tax year. Assuming you have the standard tax code of 1850L, it would be adjusted to read 1035L (11,850 minus 1,500 with the last digit removed).

        If that happens, ensure you do a full budget (see the free budget planner) to incorporate your decrease in disposable income.

      • If you owe more than £3,000:

        For bigger sums over £3,000, HMRC will send you a bill regardless of the point in the tax year and give you 30 days in which to cough up. If you cannot make the payment, don't worry – you can call the tax office and arrange a repayment schedule.

        In cases where the underpayment has been quite serious – for example you have a couple of rental properties you have not declared income on – you may be required to enter the Self Assessment system and maybe pay interest and fines.

    • HMRC has a right to ask for backdated interest on the tax owed to put itself back in the 'commercial position it would be in' had you paid on time. However, if your tax shortfall is a one-off through a tax code error, you will probably be let off.

      If the amount you owe is above £3,000, you are put into the Self Assessment system. In this case, if your backdated payment is due on 31 January (the self assessment deadline) and you don't cough up by 28 February (30 days later), you will be hit with a penalty of 5% of the tax outstanding. You'll need to pay this again on 31 July, and the following 31 January if you've still not coughed up, plus 3% interest.

    • For most, there are no 'challenges' allowed against payment deadlines when it comes to the taxman – just consequences of missing them.

      For more information read the HMRC's 'Time to Pay' guidance and what to do if you're in difficulties.

    • In this case you should inform the HMRC of your hardship (and be able to back it up).

      In some extreme cases the underpayment could be wiped. One example might be if your underpayment came from a past salary, and you're now retired earning only the state pension. It's unlikely for most people but worth discussing – see the tax help agencies at the end of this guide.

Please report successes/failures getting money back in the tax code calculator successes forum discussion

Step 4: 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 behind altogether, your tax code may change, so it can be worth getting in touch with HMRC to establish your new tax code.

A phone call today can save an awful lot of hassle and expense in the future...

Get free tax help

This guide is to give you general information about tax codes to help see if you're on the right track. Yet 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 are struggling:

Tax Aid: Lots of info's available here, but TaxAid can only help those on a low income who can't resolve their own issues with HMRC.

Citizen's Advice Bureau: Visit Citizens Advice's website to get the number of your local Citizen's Advice Bureau.

Low Income 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 you're aged over 60, you can try Tax Help for Older People or call 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.