File a Self Assessment tax return

This article explains how to file your completed Self Assessment tax return directly to HMRC using FreeAgent.

Once you've filed your Self Assessment tax return and paid your tax bill to HMRC, find out how to explain a Self Assessment payment to HMRC.

Before you start

There are some things you should check before filing your tax return:

1. Check your Unique Tax Reference number

Make sure that the Unique Tax Reference number (UTR) in your FreeAgent user profile is correct and matches your personal UTR in your HMRC online services account.

'Unique Tax Reference' box highlighted on User Details page.

2. Check that you can log in to your HMRC online services account

Make sure that you can log in to your HMRC online services account using your Government Gateway credentials. If you’re unable to log in, please see the following HMRC guidance.

3. Check that Self Assessment has been enabled as a service

Once logged in to your HMRC online services account, make sure that Self Assessment has been enabled as a service.

If you haven’t filed a Self Assessment tax return yourself before, for example if your accountant was doing this for you previously, you may need to log in to your HMRC online services account and authorise Self Assessment as a service.

Self Assessment page of HMRC Online Services website.

If Self Assessment hasn’t been enabled as a service, select ‘get online access to a tax, duty or scheme’ and follow the steps provided. Please note that if you do need to do this, HMRC will send an activation code to you in the post which can take up to 10 days to arrive. Once you’ve successfully enrolled for online filing, you’ll see a notice advising of return deadlines.

'get online access to tax, duty or scheme' highlighted on Self Assessment page of HMRC online services website.

Preparing to file your Self Assessment tax return

Navigate to the ‘Taxes’ tab at the top of the screen and select ‘Self Assessment’ from the drop-down menu.

'Taxes' drop-down menu with 'Self Assessment' highlighted.

Make sure your name is displayed in the show drop-down menu.

Example user name shown in drop-down menu.

Select the relevant tax year from the list or from the ‘History’ drop-down menu.

Tax year column highlighted on Self Assessment Summary page.

To file your return, select 'Prepare to file online' at the top of your Self Assessment tax return.

'Prepare to file online' button highlighted at the top of the return.

If your information is not complete, FreeAgent will warn you that you haven’t filled in all of the required information.

Pop up warning of missing information in Self Assessment highlighted.

Please note that you must select ‘No’ for any sections of the tax return that you don't need to fill in.

'No' button highlighted in Tax Reliefs area meaning further questions are hidden.

Use the tabs at the top of the return to navigate between the pages of your tax return. Incomplete sections are marked with an orange exclamation mark.

Six tabs highlighted at the top of the return.

Once your information is complete, we strongly advise doing the following three checks:

1. Does FreeAgent support all the pages you need to fill in?

Check that you don't need to fill in a page that FreeAgent doesn’t currently support. These include:

If you need to complete any of these pages, you won't be able to use FreeAgent to submit your Self Assessment tax return.

2. Have you completed everything you need to?

Check that you’ve completed all the relevant pages, sections and boxes on your tax return. Please note that FreeAgent won't know which of these apply to you.

3. Ask your accountant to review your return

If you use FreeAgent with your accountant, ask them to check your Self Assessment tax return. They can even submit the return to HMRC on your behalf through FreeAgent.

Filing your Self Assessment tax return to HMRC

Once you’ve checked all of the information is complete and correct on your tax return, enter your Government Gateway ID and password, then select 'Submit Self Assessment'.

Make sure that your Government Gateway credentials are being entered manually and not being auto-filled by your browser. If any of your details are being auto-filled, you should delete the auto-filled information and enter your Government Gateway ID and password manually instead, just as you would enter it to access your HMRC online services account.

'Submit Self Assessment' button highlighted at the bottom of the page.

Once you’ve submitted your Self Assessment tax return, the status of the return is marked as 'Pending' while FreeAgent sends and confirms the return with HMRC.

Once this is complete and confirmed with HMRC, the return status will be changed to 'Filed with HMRC'. The IR Mark on your tax return in FreeAgent shows that HMRC's systems have received the filed return.

It can take a couple of days for HMRC's systems to update to show the return as filed in the online tax account, but the ‘Filed with HMRC’ indication and the IR Mark are proof of filing that you can show to HMRC if needed.

Status showing 'Filed with HMRC' highlighted within panel to the right of the return.

When a Self Assessment tax return is filed directly with HMRC, or marked as filed, the relevant tax basis period will be locked, restricting the changes that can be made to transactions or items within that period.

Please note that it can take up to 72 hours for your tax return to be processed and updated on your HMRC account.

Why has my Self Assessment tax return failed to submit?

If there is a problem with filing the return, you will see an error message at the top of the ‘Main Return’ page and the status will be marked as 'Rejected'.

Status showing as 'Rejected' within the panel to the right of the return.

These are the most common reasons for returns failing to submit successfully:

  • a wrong Unique Tax Reference number
  • HMRC’s system is down
  • certain inaccuracies in the figures

Make the necessary correction(s) to your Self Assessment tax return. If there are inaccuracies in your figures, FreeAgent should flag these at the top of your return. Once you have made the necessary correction(s), select 'File Online with HMRC' again and follow the steps to file the return again with HMRC. The status of the return will be then marked as 'Pending (locked)' while FreeAgent sends and confirms the return with HMRC.

How do I correct mistakes on my tax return after it’s been filed to HMRC?

If you’ve filed your Self Assessment tax return but you need to make a correction, you'll need to unlock the return in FreeAgent. To unlock your return, navigate to the relevant return and then select 'Unlock return' in the top-right corner.

'Unlock return' button highlighted in the top-right corner of the return.

Select 'Unlock return' in the pop-up window to complete the process.

Pop-up asking user to confirm unlocking Self Assessment return.

Once the return is unlocked, you can make the necessary changes to any of the pages.

Once you have finished editing, you’ll need to complete the filing process again to submit your accurate amended return to HMRC. If you do not complete the filing process, the return will remain marked as ‘Unfiled’ in FreeAgent.

Status showing 'Unfiled' highlighted within panel to the right of the return.

Please note that you can file your return up to a maximum of nine times and all amended returns must be filed within 12 months of the original due date.

Marking the return as filed if you don't file through FreeAgent

If you don't file your Self Assessment tax return through FreeAgent, for example if your accountant uses different software to file the return, you can still mark it as filed in FreeAgent by selecting 'Mark as filed' on any of the tax return pages.

'Mark as filed' button highlighted at the top of the return.

How do I correct mistakes on my tax return after it’s been marked as ‘Filed’?

If you discover a mistake on your Self Assessment tax return once it has been marked as ‘Filed’, you can still correct it. To do this, select the 'Mark as unfiled' button in the top-right on any of the tax return pages.

Mark as unfiled' button highlighted at the top of the return.

Next, make any necessary changes and ensure that the return in FreeAgent matches what you filed with HMRC.

Once you have finished, select ‘Mark as filed’ in the top-right corner.

Mark as filed' button highlighted at the top of the return.

Locking of data once your return is filed

Once you have filed your Self Assessment tax return to HMRC through FreeAgent, your accounts should now be finalised and your business accounting records will automatically be locked to the end of the period covered by your tax return.

You will receive an error message if you try to create or amend any of the following items which are dated before the end of the basis period:

If you discover that you’ve made a mistake on your tax return, you'll be able to file an amended return.

Opening balances in a locked period

If you create any new stock items or user mileage balances within a locked period, you will need to set an opening balance of zero, and you won't be able to change the opening balance of any existing bank accounts once your accounts are locked.

Opening balances that are created through the trial balance or by creating updated journal entries, follow the same rules as any other journal entries, so you won't be able to enter any new opening balances or adjust your existing ones after your accounts are locked. New bank account opening balances are also locked.

Printing your Self Assessment tax return

You can print your completed Self Assessment tax return pages directly from your web browser by pressing either ‘ctrl' + 'p’ if you’re using a PC or ‘cmd' + 'p’ if you're using a Mac. Depending on your web browser, you may also be given the option to create a PDF.

You can also print a version of the SA302 form from the Self Assessment area of FreeAgent once you’ve completed and filed your tax return.

HMRC works with mortgage providers to encourage as many of them as possible to accept documents equivalent to the SA302 form that are printed from commercial software. If your mortgage provider will not accept this document printed from FreeAgent, you will need to request a paper copy of your SA302 from HMRC.

Once you've paid your Self Assessment tax bill to HMRC, find out how to explain a Self Assessment payment to HMRC.

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