From the beginning of September HM Revenue & Customs (HMRC) has started to send calculations (form P800) telling you if you have paid too much or too little tax for the tax years 2008-09 and 2009-10.
Not everyone will get a calculation, only those who have paid too much or too little tax. So do not worry if you do not receive one.
What you need to do with your tax calculation
If you receive a calculation, it is important you check it to make sure you agree with the information included. If you agree with the calculation you do not need to do anything, but keep it safe.
Please make sure you read the notes that came with the calculation as these will help you understand what it means. You can read the notes online by going to www.hmrc.gov.uk/P800.
HMRC will not be issuing copies of forms P800 to agents so, if you are represented by an agent, please show the calculation to them.
If you have paid too much tax
HMRC will automatically send you a repayment, usually within a week.
If you have paid too little tax
If the underpayment is under £2000, HMRC will automatically include the amount you have underpaid in your tax code for 2011-12. This spreads the collection of the underpayment throughout the year.
If the underpayment is under £2000, but the coding deduction causes hardship, you can ask for the underpayment to be included in your tax code over a longer period.
If the underpayment is £2000 or more, HMRC will write to you and ask for direct payment. You should contact HMRC on 0845 3000 627 if you wish to discuss a repayment schedule.
There are specific, limited, circumstances in which HMRC can agree to forgo collection of an underpayment where information they held was not used at the right time. There are details on the HMRC at www.hmrc.gov.uk/esc/esc.htm
If you think this applies to you, or you need further information, contact HMRC on 0845 3000 627.
What to do if you think that your tax calculation is wrong
If you do not agree with something included in the calculation, you can contact HMRC on 0845 3000 627. Or you can write to HMRC at the address shown on the calculation.