There is an online tool, developed by HMRC, that allows taxpayers to check if they need to notify HMRC about additional income. The online tool can be found at www.gov.uk/check-additional-income-tax.

You are required to submit a self-assessment return if any of the following 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);
• you were a partner in a business partnership;
• you had a total taxable income of more than £150,000 in 2023-24 (£100,000 in 2022-23);
• you had to pay Capital Gains Tax when you sold or ‘disposed of’ something that increased in value; or
• you had to pay the High Income Child Benefit Charge.

You may also need to send a tax return if you have any untaxed income, such as:

• money from renting out a property;
• tips and commission;
• income from savings, investments and dividends; or
• foreign income.

There could be other reasons why you may be required to register for self-assessment and therefore using HMRC’s online tool can help you check if you are required to submit a return.