How to claim back tax if you complete a Self Assessment

8 min read
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If you pay tax by completing a yearly Self Assessment tax return, whether you are a business owner, sole trader, or self-employed, there may be occasions when you are owed money back from HMRC. In this guide, QuickBooks explains how to claim your Self Assessment refund.

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How do tax repayments from Self Assessments work?

Overpayments made to HMRC through a Self Assessment tax return will usually be paid to you once your tax return has been fully processed. There are three ways that HMRC will make a return payment to you, with each of these depending on factors like your original method of payment, or money you may already owe HMRC.

You can request that HMRC pay back any tax overpayments in one of the following ways:

  • Directly into your bank account.

  • Sent back as a cheque.

  • Use the amount owed back to you to offset the balance of an upcoming Self Assessment tax liability, or any other amount of money owed to HMRC for any other reason.

Tax returns are submitted at the end of the Self Assessment deadline, which is usually on the 31st of January each year. You will receive your Self Assessment repayments earlier by submitting a tax return before the final date of the 31st of January, particularly because this will be one of the busiest periods for HMRC to process Self Assessments. 

For those that complete their Self Assessment online, you are likely to receive any repayments earlier than those that submit a Self Assessment through a paper form. Be aware that repayments can be delayed as HMRC may question the information provided in your Self Assessment. This can happen if HMRC suspects any fraudulent activity related to people incorrectly claiming tax back.

As stated above, if you already owe an amount to HMRC for tax credits overpayment, or any other upcoming payment to the HMRC, then the amount you receive back from your Self Assessment may be reduced to offset any payments owed. Bear in mind that you will also need to state how you would like to receive any money owed to you on your Self Assessment form, as failing to do this may cause a delay in receiving your refund. 

Making sure you claim back any money you are owed is important, particularly as you can speed up this process by proactively chasing any money the HMRC owes you. If you are a business owner, then claiming a Self Assessment refund is a great way of improving your cash flow

How can I claim a Self Assessment refund if there was a mistake on my tax return?

If you have made a mistake on your Self Assessment tax return, you will usually have up to 12 months from the 31st of January each year to inform HMRC and correct the error, however, you will need to wait 3 days after the date of filing your original Self Assessment before making any amendments.

You can amend your online tax returns by visiting the website for Self Assessments, and following these steps:

  • Sign in to your account using a Government Gateway ID and password.

  • Go to ‘Your tax account’ and select ‘Self Assessment account’.

  • Select ‘More Self Assessment details’.

  • Go to ‘At a glance’.

  • Select ‘Tax return options’.

  • Find the tax year you wish to amend.

  • Make any necessary amendments to this tax return and file it on the system.

If you instead completed a paper Self Assessment using an SA100 form, then you will need to send an amended copy of this form, along with all supplementary pages, writing ‘Amendment’ on each page and including your Unique Taxpayer Reference number (UTR).

Any refund you are owed from an amended Self Assessment will not be automatically paid back to you, however, and you will need to contact HMRC directly to claim your money back either by telephone, or by logging onto your HMRC online services account and clicking ‘request a repayment’.

Can I claim if it’s too late to amend my tax return?

HMRC has a process in place that may allow you to claim a repayment of overpaid tax even after you have missed the deadline, known as ‘overpayment relief’.

This type of claim officially replaced the old ‘error or mistake relief system’ that was in effect until the 1st of April 2010. The purpose of overpayment relief is to allow taxpayers to claim relief for a period of overpaid tax where it is not possible to make a claim through any other means, such as a Self Assessment completed on-time.

You can make a claim for overpayment relief up to 4 years after the tax year of the Self Assessment you wish to amend. In order to claim for overpayment relief you must write to HMRC directly, including the following information:

  • State that you are making a claim for overpayment relief.

  • State the tax year or accounting period you made an overpayment on.

  • Explain why you believe an overpayment was made during this period.

  • State whether you have previously made an appeal for this overpayment.

  • Provide evidence of your tax overpayment for the relevant period.

  • Sign a declaration stating that the information provided in your claim is relevant, correct, and complete to the best of your knowledge.

  • State the amount you overpaid during this period.

What does a security check mean on a tax return?

Security checks are standard practice for all Self Assessment tax returns filed to HMRC, which provides the government the means to check against fraudulent tax claims, but you will most likely be unaware of this process for the most part. However, there may be times when HMRC need to contact you directly to verify the information you have provided in your Self Assessment.

If you receive a request for information based on a security check from HMRC, this may delay any repayments you are owed from your Self Assessment.

How long do HMRC security checks take?

There is no set time for how long a security check will take to clear, however, HMRC advises that there is a 30-day deadline for responding to a request for further information or evidence. You may have to pay a penalty, fine, or have your Self Assessment closed if you fail to respond within this 30-day window.

Security checks most commonly occur in connection with Construction Industry Scheme (CIS) refunds, as there are usually large sums of money related to these types of claims.

It is important to respond to any request for information from HMRC in a timely fashion. It may be the case that you have a payment pending in your tax account that may simply require additional information before a refund is made to you.

What if my repayment is stopped for a security check?

If your Self Assessment repayment has been delayed due to an HMRC security check, then you will be unable to claim any money you are owed until HMRC have satisfied their relevant checks. 

You will receive a letter in the post detailing the information or evidence that HMRC requires to complete your claim. The letter will also be dated, with a statement that you have a 30-day window to respond to this request from the date the letter was sent.

Is there a deadline for claiming back tax from a Self Assessment?

You can claim back tax from a Self Assessment tax return for a period of 12 months after the submission deadline of the 31st of January. This is the regular period of time you are allowed to make a claim for any tax you are owed, however, there is still a 4 year period to submit an overpayment relief claim. 

It is recommended that you remain on top of making claims in a timely manner. Claiming back any owed tax for the most recent tax year is a great way of maintaining a good business cash flow.

How quickly does HMRC repay Self Assessment overpayments?

HMRC do not provide exact dates for any Self Assessment repayments, however, they do provide a general guideline of 12 weeks for overpaid returns. If you have elected to be paid by cheque, it will usually take around 2 weeks to arrive once your Self Assessment has been processed.

If you submitted your Self Assessment on or close to the deadline of the 31st of January, then you may have to wait longer to receive your payment, as this will be one of the busiest times of the year for HMRC.

Make Self Assessments easy with QuickBooks

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*individual plan pricing accurate at time of writing

Feel you’re better informed about completing your Self Assessment? The QuickBooks blog covers a wide range of business-related topics – it’s all part of our mission to help small businesses grow. Stay compliant with QuickBooks

The information on this website is provided free of charge and is intended to be helpful to a wide range of businesses. Because of its general nature the information cannot be taken as comprehensive and they do not constitute and should never be used as a substitute for legal, accounting, tax or professional advice. We cannot guarantee that the information applies to the individual circumstances of your business. Despite our best efforts it is possible that some information may be out of date. Any reliance you place on information found on this site or linked to on other websites will be at your own risk.


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