Who needs to file a Self Assessment tax return?

Who normally needs to file

You may need to send a Self Assessment tax return if HMRC cannot collect all the tax you owe through PAYE or another automatic route. Common triggers include self-employment, partnership income, property income, dividends, foreign income, Capital Gains Tax and the High Income Child Benefit Charge.

HMRC says sole traders usually need to file when they earn more than £1,000 before deducting allowable expenses. Partners in a business partnership also usually need to file.

Common examples for business owners and landlords

• You started a side business or freelance work during the tax year.
• You receive rental income from a UK or overseas property.
• You are a company director taking dividends or benefits outside payroll.
• You sold an asset and may have Capital Gains Tax to report.
• You or your partner claimed Child Benefit and your income creates a charge.
• You have savings, investment, dividend or overseas income not fully taxed at source.

When to tell HMRC

If you need to complete a return for the previous tax year and you have not filed before, you usually need to tell HMRC by 5 October. The online filing and payment deadline is normally 31 January after the tax year ends.

If you are unsure, use HMRC's checker or ask an accountant before the deadline. Waiting until January often leaves too little time to register, gather records and fix missing information.

What to prepare

• Your Unique Taxpayer Reference, National Insurance number and HMRC login.
• Income records, invoices, payslips, bank interest and dividend vouchers.
• Property income and expenses, mortgage interest statements and agent reports.
• Business expenses, mileage, pension contributions and charitable donations.

For the official checklist, see GOV.UK guidance on who must send a tax return.