The 2025/26 Self Assessment return reports relevant income and gains arising between 6 April 2025 and 5 April 2026.
Who may need to file
You may need a return if you were self-employed with gross trading income above £1,000, were a business partner, received taxable rental or foreign income, realised taxable gains or had other untaxed income. A notice from HMRC normally must be dealt with even where you believe no tax is due.
Key deadlines
- 5 October 2026: notify HMRC where required.
- 31 October 2026: paper-return deadline.
- 30 December 2026: online deadline where eligible tax is to be collected through PAYE.
- 31 January 2027: online filing and balancing-payment deadline.
- 31 July 2027: second payment on account where applicable.
Records to collect
Gather business income and expenses, P60/P11D information, pension details, bank interest, dividends, property records, capital disposals, pension contributions, Gift Aid and evidence for reliefs. Private spending is not deductible merely because it passed through a business account.
Payments on account
Payments on account are advances towards the following year’s Income Tax and Class 4 National Insurance. The balancing payment and first advance can fall due together. Reduce them only where a lower liability can reasonably be supported.
File early
Early filing provides time to find missing information and budget. It does not normally bring the 31 January payment date forward. Sole traders and landlords within Making Tax Digital may also have digital-record and quarterly-update duties from April 2026.
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