Understanding Self Assessment and your tax return
Introduction
Guidance
Self Assessment is a system HM Revenue & Customs (HMRC) uses to collect Income Tax. Income Tax is usually deducted automatically from wages, pensions, and savings. However, people and businesses with other income must report it in a Self Assessment tax return.
Do I need to file a Self Assessment tax return?
You can find out who must send a tax return and check if you need to fill in a Self Assessment return.
Self Assessment deadlines
The deadlines to submit your Self Assessment tax return for the 2025 to 2026 tax year are:
- Register (for the first time or didn't file a return last year) - 11:59pm on Monday 5 October 2026
- Paper return - 11:59pm on Saturday 31 October 2026
- Online return - 11:59pm on Saturday 31 January 2026
You must also pay the tax you owe by 11:59pm on Sunday 31 January 2027.
This guide will help you understand Self Assessment, including how to register for Self Assessment with HMRC, how to file your first Self Assessment tax return, and key deadlines for Self Assessment.
Developed with:
