How long do you have to amend a tax return in Australia?

If you realise you made an error or omission on a lodged tax return, you can request an amendment. The time limits and process depend on your circumstances.

Standard amendment period: For most individuals (those who are not companies or part of complex arrangements), the ATO can amend your assessment within 2 years of the date your original assessment was issued. This means you can also request an amendment within this 2-year window. After 2 years, the ATO generally cannot amend your assessment, and you cannot request an amendment either.

Extended period for fraud or evasion: If there is fraud or evasion, the ATO's amendment period is unlimited — there is no time limit.

How to request an amendment:

• Online through myTax (myGov) — the simplest method for minor corrections
• By completing a new tax return with the correct figures (some agents prefer this)
• By writing to the ATO or calling them to explain the error
• Through your registered tax agent

If you owe more tax: If the amendment means you owe additional tax, interest (GIC) will be charged from the original due date. If the underpayment resulted from a genuine mistake rather than intentional evasion, penalties may be reduced or waived.

If you are owed a refund: The ATO will refund the difference. Note that the ATO itself can also initiate amendments within the 2-year period (4 years for 'full self-assessment' taxpayers such as those with business income), so keep records for at least 5 years after lodgement.