You must tell HMRC by 5 October if you need to complete a tax return and have not sent one before. You can tell HMRC by registering for Self Assessment.
You must send a tax return if any of the below apply.
- you were self-employed as a ‘sole trader’ and earned more than £1,000 (before taking off anything you can claim tax relief on, or taking off the personal allowance – as such, this is turnover – not profit)
- you were a partner in a business partnership
- you had a total taxable income of more than £150,000 (such as from employment)
- you had to pay Capital Gains Tax when you sold or ‘disposed of’ something that increased in value (usually this relates to property)
- you had to pay the High Income Child Benefit Charge
You can also use HMRC’s online checker to verify if you need to submit a return.