How to Claim a Tax Refund via Self-Assessment in the UK

If you’re on Self-Assessment and happen to overpay your tax, there’s no need to worry about filing a separate claim to get your money back. The process is simple—any tax repayment owed to you is handled directly through your Self-Assessment tax return. It’s a straightforward system designed to save you time and effort.

In the following sections, we’ll guide you through how it works, ensuring you know exactly what to do to claim what’s yours.

How do Tax Repayments Through Self-Assessment Work?

If you overpay tax on your income and you complete a Self-Assessment tax return, HMRC will deal with your repayment once they have processed your tax return.

You can state in the tax return how you would like the repayment to be paid to you. You can have it:

• paid directly into your bank account,
• paid to you by cheque, or
• deducted from your next Self-assessment tax liability, for example, against the next tax year’s ‘payment on account’ if you are due to make one.

Alternatively, if you owe HMRC another amount, for example, a tax credit overpayment, you might ask them to ‘offset’ the repayment against that amount. This means they will take the amount you are due to be repaid off the other amount you owe. They will then repay any remaining repayment, or you will have to pay the rest if you still owe some.

How do I Claim a Refund if I Made a Mistake on My Tax Return?

Sometimes, you may make a mistake on your tax return and pay too much tax.

In this situation, you need to amend or correct your tax return first within the appropriate deadline. Once HMRC has processed the amended tax return, they will send you any repayment due or offset it against other amounts that you owe.

However, any refund will not be automatic; you will have to request HMRC to address it. You can do this by logging into your HMRC online services and clicking ‘Request a repayment’ or by contacting them to request repayment.

There are time limits for correcting your tax return. The normal limit is 12 months from 31 January after the end of the tax year. For example, the normal deadline for amending your 2019/20 tax return is 31 January 2022, and a 2020/21 tax return is 31 January 2023.

How do I Claim a Refund if it is too Late to Amend My Tax Return?

If you made a mistake in your tax return and paid too much tax but only realised after the deadline for amending the tax return has passed, you may still be able to claim a repayment of the overpaid tax of 4 years from the end of the relevant tax year.

In this situation you will need to write to HMRC and tell them about your mistake. You can write to HMRC using the postal address on the most recent correspondence you have from them or to HMRC PAYE and self-assessment queries address.
HM Revenue & Customs
BX9 1AS

Your letter should:

• provide your full personal details—your name, address, national insurance number, and unique taxpayer reference (‘UTR’).
• refer to the tax year to which the repayment relates.
• include as much information as possible about why you think you have paid too much tax and the mistake you made.
• enclose evidence of the tax you have paid, including copies of P60s and P45s if you have them—keep the originals.
• say how you would like to receive any repayment – you can have it paid directly into your bank account, paid by cheque, or deducted from your next self-assessment tax liability.
• be signed and dated in ink.

Timing

You complete your tax return after the end of the tax year before the submission deadline (31 January of the following year). The sooner you submit your tax return, the sooner you will receive your repayment or offset. If you submit your tax return online rather than on paper, it might be dealt with sooner, and you will get your repayment faster.

Once HMRC has processed a self-assessment tax return, most repayments will be issued automatically when the repayment instructions (e.g., account details) are provided in the tax return.

You may need to prompt HMRC to issue refunds in certain cases, such as when you do not state how you would like to receive the repayment on the return, the amount involved is small, or any signals are present that stop automatic issues.

Security Check

HMRC may also want to check some things before sending your repayment as part of its aim to prevent people from claiming tax back fraudulently. If you have been waiting several weeks to hear back from HMRC about your refund, we suggest you contact them to find out what is happening.

More recently, HMRC has started sending out letters to verify repayment claims more widely in response to an increase in repayment fraud. Where HMRC’s risk assessment identifies that a repayment claim is likely to be fraudulent, they will not make the repayment unless they receive a response to the letter.

Conclusion

In conclusion, claiming a tax refund through Self-Assessment is straightforward if you overpay tax, provided you follow the appropriate steps. Ensure you state your preferred method of repayment on your tax return and submit it promptly, preferably online, to expedite processing. If you make a mistake, amend your return within the deadlines or write to HMRC if it’s too late to amend.

Be prepared for possible security checks, as HMRC may verify claims to prevent fraud. Stay proactive by providing accurate information and following up with HMRC if there are delays.