Tax Deadlines & Important Dates

Which tax dates should you know? 

Most employees have their tax dealt with automatically through PAYE, so they do not usually need to file a tax return. 

​

However, if you need to use Self Assessment, several dates are important. 

​

6 April 

The new UK tax year begins. 

​

5 April 

The tax year ends. 

​

For example, the 2026–27 tax year runs from 6 April 2026 to 5 April 2027. 

​

5 October 

If you need to complete a Self Assessment return for the previous tax year and have not already registered appropriately, you generally need to tell HMRC by 5 October. (GOV.UK) 

​

31 October 

This is normally the deadline for HMRC to receive a paper Self Assessment tax return. (GOV.UK) 

​

31 January 

This is usually the most important Self Assessment deadline. 

​

By 11:59pm on 31 January, you normally need to: 

• submit your online tax return; and 

• pay the Self Assessment tax you owe. 

 

Late filing or late payment can result in penalties and interest. (GOV.UK) 

​

Key takeaway 

For most young employees, PAYE handles tax automatically. But if you become self-employed or need Self Assessment, deadlines become your responsibility.