Self Assessment tax returns

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Sending a return

You can send a tax return by either: 

  • submitting an online return  
  • sending a paper return 

You can get help filling in your return. 

When to send your tax return 

Check the filing deadlines. The deadline for sending a paper return is before the deadline for an online return. 

You can send your return any time after 5 April. Sending it earlier means you: 

If you do not know your profit for the whole tax year  

You might not know what your profit will be for the whole tax year if, for example:  

  • your ‘accounting period’ ends at a different time to the end of the tax year 
  • your ‘accounting period’ is different to your ‘basis period’ 
  • you’re waiting for a valuation 

An ‘accounting period’ is the period which a business’s accounts are made up to (often 12 months) and gives the business year end. This can be different to the period used to identify the profits taxable in any particular tax year (also known as a ‘basis period’). 

If you do not know what your profit will be for the whole tax year before the reporting deadline, you should work out what it’s likely to be (known as ‘provisional figures’) and include those. 

You should tell HMRC that you’ve used provisional figures when you submit your return. 

When you find out what your profit was for the whole tax year, you’ll need to  change your return. You have 12 months from the Self Assessment deadline to make these changes. 

If more tax is due, you’ll need to pay interest on the difference between your estimates and the final figures. The interest will be worked out from the original due date for payment. If you have overpaid tax then you’ll get interest paid to you. 

Submit an online return  

You can file your Self Assessment tax return online.

Send a paper return 

If you need a paper copy of the main Self Assessment tax return you can: 

If you need to send a tax return for trustees of a registered pension, you must download form SA970. 

You can download all other forms and supplementary pages. 

After sending your paper return, you can check when to expect a reply from HMRC. 

Use commercial software to send a return 

You can use commercial software: 

  • for a partnership 
  • for a trust and estate 
  • if you get income from a trust 
  • if you lived abroad as a non-resident 
  • if you’re a Lloyd’s underwriter 
  • if you’re a religious minister 
  • to report profits made on selling or disposing of more than one asset (‘chargeable gains’) 

Find a commercial software supplier.

View a printable version of the whole guide

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