Self assessment – key dates

31 January 2026

– First payment on account due for 2025/26 tax year.

31 July 2026

– Second payment on account for 2025/26 tax year.

5 October 2026

– Deadline for notifying HMRC of new sources of income (including the Child Benefit charge) if no tax return has been issued for 2025/26 tax year.

31 October 2026

– Deadline for submission of 2025/26 non-electronic returns.

30 December 2026

– Deadline for submission of 2025/26 electronic tax returns if ‘coding out’ of eligible underpayment is required.

31 January 2027

– Deadline for filing electronic tax returns for 2025/26. Balancing payment due for 2025/26 tax year. First payment on account due for 2026/27 tax year.