Who Needs to File a Self Assessment Tax Return?
You must file a Self Assessment return if any of the following applied to you in the tax year:
- ✓You were self-employed as a sole trader and earned more than £1,000
- ✓You were a partner in a business partnership
- ✓Your income was over £150,000 (even if all through PAYE)
- ✓You had untaxed income over £2,500 — such as rental income, dividends, or foreign income
- ✓You owe capital gains tax (from selling investments, property or business assets)
- ✓You received Child Benefit and either you or your partner earns over £60,000
- ✓You were a company director with untaxed income
- ✓You made Gift Aid donations and want to claim higher-rate relief
What If I Am Employed and Have Small Side Income?
If you have a job with PAYE and a side income, you only need to file a Self Assessment return if that side income exceeds £1,000 (the trading allowance). Between £1,000 and £2,500 of untaxed income, HMRC may collect the tax through your tax code rather than requiring a return — but you should contact HMRC to confirm.
If your side income exceeds £2,500, a Self Assessment return is required. See our guide on how to file your return.
What If I Was Self-Employed but Earned Very Little?
The trading allowance means you do not need to register for Self Assessment if your self-employment income is £1,000 or less in the tax year. You also do not need to report it to HMRC. If you earned above £1,000, you must register and file even if your profit after expenses is zero or negative.
How to Check If You Need to File
HMRC provides an online tool at gov.uk that helps you check whether you need to complete a return based on your specific circumstances. If HMRC has already sent you a letter saying you need to file, you must do so even if you believe you do not meet the normal criteria.
Once you are registered for Self Assessment, you must file every year until you formally tell HMRC to deregister. If you stop being self-employed, contact HMRC to cancel your Self Assessment registration.