When does the tax year end? Start date for new 2023-24 tax year and when you need to fill out a tax return

When tax year ends and a new one begins, you should be notified by HMRC if you are required to fill out a return

end of year working out inland revenue tax self assessment form with calculator

Freelance reporter April 3, 2023 3:48 pm (Updated 3:49 pm )

The current tax year is set to end on Wednesday with the 2023-24 tax year starting the following day.

The UK tax year always follows this schedule, starting on 6 April and ending on 5 April the next year.

Most self assessment tax returns for the most recent tax year need be submitted online by the following 31 January.

Here’s everything you need to know.

When does the new tax year start in 2023?

The UK tax year always follows the same schedule, starting on 6 April and ending on 5 April the following year.

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The explanation can be traced back to 1752, when Britain introduced the Gregorian calendar that we still follow today.

Under the old Julian system, the tax year began on New Year’s Day, which fell on 25 March in the Gregorian calendar.

To ensure it did not lose revenue, the Treasury decided to keep the 1752-53 tax year at 365 days, rather than readjusting so it lined up with the calendar year.

This meant the 1752-53 tax year ended on 4 April, with the new tax year starting on 5 April.

In 1800, the dates shifted by a day, since it was not a leap year in the Gregorian calendar, but would have been under the Julian system.

This meant the 1800-01 tax year ran from 6 April to 5 April, and it has remained on that schedule ever since.

Who needs to fill in a self-assessment tax return?

You must send a tax return if, in the last tax year (6 April to 5 April), any of the following applied:

You may also need to send a tax return if you have any untaxed income, such as:

You can use this online checker to see if you need to fill in a tax return.