Claiming a tax refund may be necessary because you have been overcharged on account of an incorrect Pay As You Earn Coding Notice. This can happen if you have changed jobs a few times recently, if you have more than one job, or because of a clerical error. You may wish to claim a tax refund if you are unemployed or have made errors on your self-assessment form.
If you are an employee
Telephone HMRC to explain the problem. Give them your details including your National Insurance number. Have your P45 or P60 form handy and wage slips for the period in question, so you can refer to them during the conversation. Note that HMRC may need to send you a P800 Tax Calculation form, depending on your circumstances.
Complete the P800 Tax Calculation form as soon as it arrives. Remember to fill in all the relevant sections, giving information about your employment and benefit history, pensions and other income. Include your supporting documentation to aid HMRC as they process your claim. Send the form back quickly.
Await the arrival of a letter from HMRC telling you about the status of your claim. With a bit of luck, it will include a cheque for the full amount of tax you overpaid.
If you are unemployed
Note that if you are in receipt of Jobseeker's Allowance or Employment and Support Allowance or Incapacity Benefit that is subject to tax, you cannot normally claim a tax refund straight away.
Take parts 2 and 3 of your form P45 to your Benefit Office.
Any tax refund you are entitled to should be paid via them.
If you are self-employed
Make an amendment to your self-assessment tax return within twelve months of submitting it. If you submitted it online, log into your Self Assessment Online account.
On the "At a glance" page, click "make an amendment to this return." Choose to add a new section, amend a figure or delete a section. Make changes as necessary then resubmit the form.
Write to HMRC if you submitted your tax return on paper. Attach the amended return pages, marked "amendment."
Telephone HMRC on: 0845 300 0627
Write to HMRC at: HM Revenue & Customs Pay As You Earn PO Box 1970 Liverpool L75 1WX
Any tax refund you are owed for this tax year should be repaid along with your wages.
Tax refund claims are subject to strict time limits, so ensure you make a claim as soon as possible.