How to correct mistakes on a self assessment

1. Identify the error

The first step is to thoroughly review your submitted tax return and identify the exact nature of the mistake. Common errors might include incorrect figures, missing income, or inaccurate deductions. Take note of what needs to be corrected to ensure you address every issue.

2. Check the deadline for corrections

The HMRC allows you to make corrections to your self-assessment up to 12 months after the filing deadline. For instance, if you filed your tax return for the 2022/2023 tax year by the 31st January 2024 deadline, you have until 31st January 2025 to amend it. Missing this deadline might require additional steps, such as filing an appeal or submitting an overpayment relief claim.

3. Log into your HMRC account

To correct a mistake online, log in to your HMRC account. This is the quickest and easiest way to make amendments. Once logged in:

• Navigate to the "Self Assessment" section.

• Click on "More Self Assessment Details."

• Choose "At a glance" and then select "Tax Return Options."

• Here, you'll see an option to amend your return. Select the tax year you wish to correct.

4. Make the necessary amendments

Once in the amendment section, make the necessary changes. Be thorough and double-check your corrections. It's helpful to have all your paperwork handy, including income statements, receipts, and any other documentation you used for your original submission. After entering the correct information, you can resubmit your amended return.

5. Check your amended tax calculation

After you've made your changes, HMRC will automatically recalculate your tax liability. It's essential to review this new calculation to ensure everything adds up correctly. If your changes result in additional tax owed, you'll need to pay this amount promptly to avoid interest and penalties.

6. Submit the correction

Once satisfied with your corrections and the new tax calculation, you can submit your amended return. HMRC will process your amendments and, if necessary, issue an updated tax bill or refund. You'll receive a confirmation from HMRC when your amendment has been successfully processed.

7. Track the progress of your amendment

After submitting your correction, you can track its progress through your HMRC account. It typically takes a few weeks for amendments to be processed, though this can vary depending on the complexity of the changes.

8. What if you miss the amendment deadline?

If you realise an error after the 12-month amendment window has closed, you still have options:

• Write to HMRC: You can send a letter to HMRC explaining the mistake and providing the correct information. This is known as an "overpayment relief" claim, but it must be made within four years of the end of the tax year in question.

• File an Appeal: If HMRC issues a penalty due to an error you believe is incorrect, you have the right to appeal.

9. Avoiding future mistakes

To avoid future mistakes, consider using a professional service to assist with your self-assessment. With our service, filing your self assessment is easy and straightforward. Simply fill out our simple questionnaire, and you'll receive a personalised, step-by-step guide tailored to your unique tax situation—all for just £9.99. This not only saves you time but also gives you peace of mind knowing that your tax return is accurate.

Correcting mistakes on your self-assessment doesn’t have to be a headache. By following the steps outlined above, you can ensure your tax return is accurate and avoid any potential penalties. And remember, if you’re ever in doubt, professional assistance is always available to make the process even smoother.

By staying proactive and informed, you can navigate the self-assessment process with confidence.