Can I amend my Self Assessment tax return after filing?

Filing your tax return each year can be a lot to keep track of, and sometimes small details slip through the cracks. The good news is that yes, you can amend your tax return. HMRC lets you go back and make changes or add any missing information to your Self-Assessment.

Until when can you amend or correct your Self-Assessment tax return?

You are allowed to amend or correct your tax return within twelve months of the Self-Assessment tax return deadline.
For instance, Mr A submitted his tax return for the 2024–2025 tax year, with a filing deadline of 31 January 2026. If Mr A wishes to make any amendments to his tax return, he must first wait seventy-two hours (three days) after submitting it for the 2024–2025 tax year. After this period, Mr A may amend his tax return up until 31 January 2027.

Can I amend my tax return after the 12-month period provided by HMRC?

If you want to change the submitted tax return after the expiry of 12 months, you will need to write a letter to HMRC to report the information you want to include in your tax return. The following points need to be mentioned in your letter:

• The relevant tax year you want to make a correction for
• The information you want to report in your tax return
• An explanation regarding your overpaid or underpaid tax
• Your signature

You also need to keep evidence that you have paid tax through Self Assessment for the relevant period, as HMRC may ask for this at a later date.

DTax Filer makes completing and submitting your Self-Assessment tax return quicker and easier, and thousands of people already rely on it to report their taxable income to HMRC.

If you need to update any details or correct information, our software also allows you to amend your tax return. You can submit an amended return even if your original submission was made using a different method. Submit your amended tax return today.