Self-assessment tax return


Not everyone must complete a tax return. If your tax matters are simple (for example, you work all year in one workplace) you may have already paid all taxes on your earnings or pensions through the Tax Code in the PAYE (Pay As You Earn) system. However, if you have more complicated tax matters, e.g. you work in several workplaces, run a business, even if you have already paid tax through a tax code, you may be required to complete a tax return.

Circumstances in which you will always have to complete a tax return and account for tax – e.g. if you are:


  • registered as self-employed/sole trader/partnership, i.e. you run a business in the UK
  • company director Ltd
  • trustee
  • you are getting a pension from abroad
  • you earn rental income, e.g. you rent a flat for a fee
  • you receive income from abroad


If you are a self-employed person, i.e. you are registered as a self-employed/sole trader, you should be aware that you will be required to complete a Tax Return Self Assessment for each tax year in which you have operated. The tax return should also be settled if you have been registered as self-employed for only part of the year. Before completing your first tax return, you should register with the business tax department at HM Revenue & Customs (HMRC)

5 October 2020

Deadline for Self Assessment registration for the self-employed and freelancers, or additional income earners.

Register online on the GOV.UK website to receive your 10-digit Unique Taxpayer Reference (keep this safe, you’ll need it when you submit your tax returns). The process can take up to 10 working days to complete – you’ll receive a letter with a code that is required for activation.

31 October 2020

Deadline for individuals to submit paper Self Assessment tax returns if requesting underpayments of tax of £3,000 or less to be collected through 2020/21 PAYE code

If you have income from PAYE and a tax bill of less than £3,000 and want this to be collected by wage deductions over 12 months from April 2021, you must submit your paper tax return by 31 October 2020. This is subject to you having enough earnings to deduct the tax due. If you’d prefer to do this online, you have slightly longer to submit your tax return (30 December 2020).

31 January 2021

Online submission deadline for 2019/20 Self Assessment income tax returns. 

31st January is the biggest date in the tax calendar for many self-employed people and small business owners. 

If you’ve earned any income outside of PAYE tax, you’ll need to submit a Self Assessment tax return, which is the document that tells HMRC what you’ve earned and what you need to pay in tax.

Self Assessment income tax returns are due by midnight on 31st January for the previous tax year 2019/20 but get it done with plenty of time to spare so it isn’t stressful.

If you miss the deadline HMRC will charge you a penalty of £100 if it’s up to three months late (more if it’s later).