Assessment Time-Bar Calculator

1. Enter the original order date

   The 5-year clock runs from the end of that financial year (30 June).

2. Enter the notice date

   The one-year clock runs from the date the show-cause notice was issued (a further 90 days can be granted).

3. Compare both deadlines

   See days remaining, or whether either has already lapsed.

4. Confirm with a tax advisor

   Exceptions and extensions can affect the actual deadline.

The usual reason to work this out is not curiosity. A notice has arrived proposing to amend an assessment from several years ago, and the question is whether the department is still in time to do it.

If the limitation period has expired, the proceedings are barred however strong the underlying point may be. That is worth establishing before you spend effort arguing the merits.

The clock starts at the order, not the tax year

This is the error that produces the wrong answer. The five-year period runs from the end of the financial year in which the original assessment order was issued — not from the tax year the income belonged to, and not from the date you filed. A return for an old year that was assessed recently may still be well within time.

Limitation has to be raised

Being out of time is a defence, not something that happens by itself. It has to be taken, in writing, in reply to the notice. A taxpayer who engages with the merits and only mentions limitation later has made the argument harder than it needed to be.

Where this stops

This works out dates from the dates you give it. Periods can be extended or suspended in particular circumstances — where proceedings are stayed by a court, for instance — and whether any of that applies to your case is a question for someone who has read the file.