Have you paid the wrong amount of tax? - In Northern Ireland you may get a Tax Calculation (form P800) from HM Revenue and Customs (HMRC) telling you that you've paid too much or too little tax for the tax years 2008-09 and 2009-10. The calculation shows your total income and the allowances that are due to you for each of these years.
Not everyone will get a calculation, only those who have paid too much or too little tax - so don't worry if you don't get one.
If you do get a Tax Calculation, you should check the calculation carefully to make sure you agree with all the information given. You should also make sure you read the notes that come with it as these will help you understand what it means. You can read the notes online by going to www.hmrc.gov.uk/P800 .
HMRC has recently announced that they will not pursue cases where the amount owed is less than £300.
What if you don't agree with HMRC's calculation
If you don't agree with the calculation, contact HMRC on 0845 3000 627 and tell them why. Or you can write to HMRC at the address shown on the calculation.
What happens if you do agree with HMRC's calculation
If you agree with the calculation, you don't need to do anything - just keep it somewhere you can find it again easily if you need to.
If the amount you owe is under £2000, HMRC will automatically collect the money from your pay during the tax year 2011-12. This spreads repayment throughout the year, but you can ask to pay it back over a longer period of time if you need to.
If the amount you owe HMRC is £2000 or more, HMRC will write to you and ask for direct payment. You can ask to pay the money back in instalments, rather than all in one go.
You can contact HMRC by phone on 0845 3000 627.
In certain very specific circumstances, it may be possible to argue that HMRC had all the information they needed to calculate your tax correctly but did not use it at the right time. If you are able to argue this, you may be able to persuade HMRC to write off the underpayment.
For more details about this, go to the website of the Low Incomes Tax Reform Group at: www.litrg.org.uk. You can also go to HMRC's website at:http://www.hmrc.gov.uk/esc/esc.htm.
What if you have paid too much tax
If you have paid too much tax, HMRC will automatically send you a repayment, usually within a week.
To find out more about how to work out whether you've paid the right amount of tax, see Income tax allowances and amounts, Tax reliefs and The Pay As You Earn (PAYE) System.