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MARTIN Lewis is warning millions of workers to check their tax codes before April - as they could be missing out on thousands.
HMRC is currently sending out codes for the new tax year that starts on April 6 - and it's up to you to check yours is correct.
The said on his this week: "It’s your legal responsibility to check your tax code is correct.
"Millions each year are wrong and it can be a nightmare.
"If you underpay, in a couple of years you suddenly get a bill of thousands of pounds that you’ve spent.
"Or if you’re overpaying then you’re not getting the take home pay that you should."
Tax codes apply to everyone who's employed full-time or part-time, or receiving a private pension.
In most cases, HMRC will issue you a code but mistakes happen, especially if you've moved jobs or started receiving benefits for the first time over the past year.
If you've been or still are on an incorrect tax code, it's worth claiming your cash sooner rather than later as the time limit to get a rebate is four years from the end of the tax year for which you overpaid.
A tax code is usually made up of a combination of numbers and letters and is used by employers and pension providers to work out how much income tax you should pay.
Employers take the sum of money from your paycheck before it arrives in your account.
When reading your payslip, first make sure your name, address and National Insurance number is correct - and if it isn't, contact your employer's HR department.
Most of us who are basic-rate taxpayers (because we earn less than £50,00 a year) can earn £12,500 between April 2019 and April 2020 before paying tax. This is called your personal allowance.
The figure will remain the same for the 2020/2021 tax year because the personal allowance has been frozen.
The first four digits in your tax code usually represents how much you can earn tax-free.
For example, if you're currently on this year's standard code 1250L, you can earn ten times £1,250 before you have to pay a penny in tax.
But it's not the correct tax code for everybody, Martin warned.
He added: "You shouldn’t be on that if you have a company car or if you have company benefits.
"Or if you have a pension coming in or a second job."
The next thing to check for is the letter in your tax code. We've made a list of what they all mean in the box below.
THE letters in your the code on your payslip indicates how much tax you have to pay. Here's our guide to what each of the letters mean:
If you think your code is wrong then you should contact HMRC as soon as possible so that it can be put right.
You can use its online to do so, or contact .
You'll need to have your tax reference and National Insurance number, which you'll be able to find on your payslip.
Keep in mind that although correcting a tax code could mean you're due a refund, it could also lead you to find out that you've underpaid.
If you find out that you owe money, how you go about paying it depends on the amounts involved and how HMRC dealt with your case.
For example, if the taxman didn't let you know of any underpayments within 12 months of the tax year ending, you can try to have your debt written off.
You can do this by asking for a so-called , but it's not guaranteed to work.
A couple of weeks ago, Martin Lewis explained how you can boost the interest you earn on savings.
The money guru also revealed how you can save thousands of pounds on your council tax.
Plus, he shared his top tips for getting out of debt.
