Loading tools
The key dates for filing your Self Assessment return and paying tax.
The Self Assessment tax return deadlines are: 5 October (register for Self Assessment if you have not filed before), 31 October (paper return filing deadline), and 31 January (online filing deadline and balancing payment due date). The second payment on account is due by 31 July. Missing these deadlines triggers automatic penalties — even if you have no tax to pay.
This definition is for informational purposes only and does not constitute tax, legal, or financial advice. Rules may change and outcomes depend on your circumstances.
These GOV.UK and HMRC sources provide the official context for this glossary entry. The definition is educational and does not determine your individual tax position.