Financial Matters: when you might need to fill in a tax self-assessment return for the first time
Do you need to complete a self-assessment tax return this year?
A change in circumstances, like starting a small business or renting out a room, could mean that you need to complete your first ever self-assessment tax return.
While tax is usually deducted from wages, other incomes must be reported.
HMRC must be informed by October 5 if you need to complete a tax return and have not sent one before.
Who needs to check?
According to HMRC, you must send a tax return if, in the last tax year (April 6 to April 5), any of the following applied:
you were self-employed as a ‘sole trader’ and earned more than £1,000 (before taking off anything you can claim tax relief on)
you were a partner in a business partnership
you had to pay capital Gains Tax when you sold or ‘disposed of’ something that increased in value
you had to pay the High Income Child Benefit Charge and do not pay it through PAYE
you were an off payroll worker repaying a student or post graduate loan
you received untaxed income such as money from property, tips and commissions, dividends, savings, foreign income
A free online checking tool is available on GOV.UK if you are unsure if you need to complete an assessment: https://www.gov.uk/check-if-you-need-tax-return
If your circumstances have changed - for example, you have retired or are no longer self-employed, you can also use the tool to see if you can stop filing. If so, inform HMRC by January 31 2027 to avoid unnecessary reminders and penalties.
Avoiding penalties
Missing the deadline is an automatic £100 fine. Stay ahead by following these key dates:
5 October: Register with HMRC if you are new to Self Assessment
31 January: The final deadline to file online and pay your bill
Filing early does not mean you have to pay early - it just means you know exactly what you owe and can avoid the last-minute stress.
Taxpayers can register for self-assessment on GOV.UK. Alternatively, you could speak to an accountant for help and advice. They can guide you through the process to make sure you don’t miss any relevant tax reliefs or tax planning opportunities whilst still remaining compliant.