Understanding Self Assessment and your tax return

You will need to register for Self Assessment with HM Revenue & Customs (HMRC) if you have to send a tax return but didn't send one the previous year.

Self Assessment registration process time

You should note that it can take up to 20 working days to complete the registration process. You should take this into consideration to give yourself plenty of time to complete your Self Assessment return ahead of the 31 January deadline.

Watch this short HMRC video explaining how to register your new business online with HMRC so that you can complete a Self Assessment return.

Watch this short HM Revenue & Customs (HMRC) video with simple guidance on how to fill in and submit your Self Assessment tax return. This video is particularly useful if you are completing your first Self Assessment tax return.

When you use HM Revenue & Customs (HMRC) online tax return it automatically works out how much you have to pay by providing you with a result of your calculation.

View this short HMRC video explaining how to view your Self Assessment calculation:

Your tax bill refers to your bill for income tax and any Class 4 National Insurance contributions you may owe to HM Revenue & Customs (HMRC).

View this short HMRC video explaining how you pay your Self Assessment tax bill including various payment methods and payment deadline dates:

You may face paying a penalty if you don't submit your Self Assessment tax return on time. You may also face a penalty if you don't pay the tax you owe to HM Revenue & Customs (HMRC) by the appropriate deadline.

View this short HMRC video explaining the penalties that can be applied in the Self Assessment system:

View this short HM Revenue & Customs (HMRC) video explaining how you can budget and prepare ahead for your Self Assessment tax bill including how to use the Ready Reckoner tool for the self-employed and information on the budget payment plan:

If you are self-employed you may need to understand pre-trading expenses, day to day revenue expenses, capital allowances and using flat rates or simplified expenses. Access the HM Revenue & Customs (HMRC) self-employed business expenses e-learning tool.

You can also view this short HM Revenue & Customs (HMRC) video explaining expenses you can claim if you're self-employed and how to account for these in your Self Assessment tax return:

You should contact HM Revenue & Customs (HMRC) as soon as possible if you can't pay your tax bill.

If you owe less than £10,000 you might be able to arrange to pay in instalments online.

GOV.UK provide further information on what to do if you cannot pay your tax bill on time.