A key part of Self Assessment is calculating your tax (and, if appropriate, self-employed National Insurance contributions and student loan repayments) due for the tax year. In most cases, HMRC perform this calculation for you based on the information you include on your tax return. 

If you do not have all the information you need to be able to complete your tax return accurately, you can use a provisional or estimated figure. If you do this, it means you do not need to delay submitting your tax return to HMRC and risk getting a late filing penalty.

You must keep records to support the information you report to HMRC on your Self Assessment tax return or through Making Tax Digital for income tax. Here we look at what you need to keep, and for how long.

To avoid being charged a late filing penalty, make sure you understand when your Self Assessment tax return should be filed.

Registering for Self Assessment refers to the process by which you tell HMRC that you need to send a Self Assessment tax return, if you do not already do so. Once you have registered, HMRC issue you with a unique taxpayer reference (UTR), and send you a formal notice to file a tax return for a ...

If you meet HMRC’s Self Assessment criteria for a particular tax year, HMRC will expect you to file a Self Assessment tax return for that year. However, whether or not you fall within these criteria, if HMRC ask you to file a Self Assessment tax return, then you must do so unless HMRC cancel the ...