Money Saving Expert Martin Lewis says there's one thing everyone can do to improve their financial situation.
Speaking on Good Morning Britain , Martin urged all employees in the UK to check their tax code.
He warned millions of codes written on either your payslips, P45s, P60s and coding notices are wrong.
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From April 6, a new tax year started.
Martin said everyone will have received a new tax code and if it is wrong it impacts your take-home pay.
But he warned it is not employers responsibility to check your tax code.
The basic code is 1250L - when you add an extra zero on the end shows the amount you can earn before paying tax (£12,500).
But if you've changed jobs, have more than one job, get employee benefits or are receiving more than one pension, you may have the wrong tax code.
The best way to check is by using a free online calculator.
If it seems to be wrong, it could be worth taking action to check out whether you're owed any money.
You can contact HMRC on 0300 200 3300.
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Money Saving Expert Martin Lewis on how parents can claim £2000 FREE cash
