Answers · UK 2025/26
What is a tax return in the UK?
A UK tax return (Self Assessment SA100 form) is an annual form submitted to HMRC reporting all your income, gains and reliefs so HMRC can calculate the correct tax owed outside of PAYE.
Full answer
A UK tax return — formally the **SA100** form — is the document used to report income, capital gains, and claims for reliefs to HMRC each tax year (6 April to 5 April). **Who must file a tax return?** You're required to complete Self Assessment if you: - Are self-employed (profits above £1,000 Trading Allowance) - Earned above £100,000 - Have untaxed income above £2,500 (rental, foreign income, etc.) - Are a company director - Have capital gains above the £3,000 AEA - Owe the High Income Child Benefit Charge - Have income from abroad **PAYE workers:** Most employees are taxed automatically through PAYE. However, if your tax position is complex (multiple jobs, benefits in kind, underpaid tax), HMRC may issue a P800 reconciliation instead of requiring a full SA return. **What's included in the return:** - Employment income (P60 / P45 figures) - Self-employment profits (SA103 supplementary pages) - Property income (SA105) - Capital gains (SA108) - Foreign income (SA106) - Pension income and contributions - Gift Aid donations **Paper vs online deadlines:** | Method | Deadline | |---|---| | Paper return | 31 October (e.g. 31 Oct 2026 for 2025/26) | | Online via HMRC | 31 January (e.g. 31 Jan 2027 for 2025/26) | | Tax payment | 31 January | **Owe tax vs refund:** - If you owe tax, pay by 31 January to avoid interest and penalties. - If HMRC owes you a refund, it is typically issued within 5 weeks of filing — directly to your bank account (via Government Gateway) or by cheque.
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This answer is informational only and does not constitute financial, tax or legal advice. Figures are for the 2025/26 UK tax year. See our methodology and sources.