United Kingdom Self Assessment: registration and deadlines
Self Assessment has separate requirements for registration, filing and payment. A July payment deadline applies to payments on account, while late filing has its own penalties.
On this page
- Sole-trader return trigger
- Earnings over £1,000 before tax relief.
- Payment dates
- 31 January; 31 July for payments on account.HMRC, Self Assessment deadlines
- Initial late-filing penalty
- £100.HMRC, Self Assessment penalties
Who must send a return and register
A return is required for sole traders earning more than £1,000 before tax relief, business partners, people owing Capital Gains Tax, people owing the High Income Child Benefit Charge who do not pay it through PAYE, and off-payroll workers repaying a student or postgraduate loan. HMRC, Self Assessment registration (opens in a new tab).
Untaxed income, including rent, savings interest, dividends and foreign income, may also require a return. HMRC, Self Assessment registration (opens in a new tab).
Someone needing a return for the previous year must tell HMRC by 5 October if they have never sent one, or registered before but did not need a return for 2024 to 2025. Registration is the route for notifying HMRC. HMRC, Self Assessment registration (opens in a new tab).
Filing and payment deadlines
For the tax year from 6 April 2025 to 5 April 2026, the ordinary paper filing deadline is 11:59pm on 31 October 2026. Online filing and payment of tax owed are due by 11:59pm on 31 January 2027. A second payment deadline of 31 July applies to payments on account. HMRC, Self Assessment deadlines (opens in a new tab).
Late-filing penalties
HMRC publishes an initial £100 penalty. After 3 months, daily penalties are £10 up to £900. After 6 months, a further penalty is 5% of tax due or £300, whichever is greater; after 12 months, another 5% or £300 charge applies, whichever is greater. Late-payment penalties and interest are separate. HMRC, Self Assessment penalties (opens in a new tab).
All partners receive a penalty if a partnership return is late. An appeal is possible where there is a reasonable excuse. HMRC, Self Assessment penalties (opens in a new tab).
Scope
This is general information adapted from HMRC material under the Open Government Licence v3.0, without endorsement. It does not determine an individual filing obligation, penalty or payment schedule. Special filing deadlines are outside this summary. No matching calculator or worked example is available here.