Answers · UK 2025/26

Do I need to file a Self Assessment tax return in the UK?

You must file a Self Assessment return if you are self-employed with income over £1,000, earn over £100,000, have untaxed income over £2,500, receive foreign income, have capital gains above the £3,000 AEA, are subject to the High Income Child Benefit Charge, or receive taxable income not taxed at source.

Last updated: 28 May 2026Last reviewed: 28 May 2026How we verify

Full answer

HMRC requires a Self Assessment tax return in the following situations: (1) Self-employed with gross income over £1,000/year (the trading allowance). (2) Income over £100,000 in any tax year (Personal Allowance tapers from this point). (3) Untaxed income from savings, investments or rental property over £2,500/year (below this, HMRC may adjust your tax code instead). (4) Foreign income of any amount, or dual residency questions. (5) Capital gains above the Annual Exempt Amount (£3,000 in 2026/27). (6) High Income Child Benefit Charge (HICBC) — if you or your partner earned over £60,000 and receives Child Benefit. (7) You were a company director in the tax year (with some exceptions). (8) You have income from a trust or settlement. (9) You are a non-UK resident with UK income. (10) You have tax to pay that cannot be collected via PAYE. Even if HMRC hasn't contacted you, it's your legal responsibility to register for Self Assessment if you meet any of these criteria. Deadline to register: 5 October after the end of the tax year. Online filing deadline: 31 January (so for 2026/27, that's 31 January 2028). Paper deadline: 31 October 2027. Late filing penalty: £100 immediately, rising with further delays. Use HMRC's online checker or speak to an accountant if you're unsure.