When is the Self Assessment deadline?
Last reviewed:
In short: 31 January for online returns and the balancing payment, 31 October for paper returns, and 31 July for the second payment on account. All deadlines are for the previous tax year ending 5 April.
For the 2025/26 tax year (6 April 2025 to 5 April 2026), the paper-return deadline is 31 October 2026 and the online deadline plus any tax owed is 31 January 2027.
If your tax bill is over £1,000 and less than 80% is collected at source, HMRC asks for payments on account: 50% by 31 January, 50% by 31 July, each based on the previous year's bill.
Late filing triggers an automatic £100 penalty even if no tax is owed, with further penalties at 3, 6 and 12 months. Late payment is charged HMRC interest plus 5% surcharges at 30 days, 6 months and 12 months.
Primary source: gov.uk/self-assessment-tax-returns/deadlines