The short answer
If you've lodged your tax return and then found a receipt, remembered a deduction, or got an updated income statement from your employer, you can usually still fix it. In Australia this is called an amendment.
The Australian Taxation Office (ATO) says individuals generally have two years to amend, starting the day after your notice of assessment is sent to you. Sole traders have four years for the 2024-25 income year onwards. You can lodge more than one amendment in that time, and there's no fee.
When you might amend
The ATO lists these as reasons to amend:
- you didn't claim a deduction or tax offset you were entitled to
- you left out income or a capital gain
- you answered a question incorrectly
- something changed after you lodged, such as your employer finalising or updating your income statement, a revised payment summary, or repaying income you were overpaid
If you think the ATO made the mistake when processing your return, contact them first. They may be able to sort it out without an amendment.
Wait for your notice of assessment first
Don't amend straight after lodging. The ATO asks you to wait until your original return (or an earlier amendment) has been processed, which is when your notice of assessment arrives. Amending before then can slow things down.
How to do it
On myGov (most people). Sign in to myGov, open the ATO from your linked services, choose Manage tax returns, then Amend next to the year you want to change. Change the amount, or add a new deduction or income type, and submit. You can also do this in the ATO app. This works even if an accountant lodged the original.
Through your accountant. Ask them to lodge the amendment for you. They can do it even if they didn't lodge the original.
By paper or letter. If you can't do it online, there's a paper form (Request for amendment of income tax return for individuals), or you can write to the ATO. These take longer.
How long it takes
The ATO says an online amendment takes about 15 business days to process. Paper forms and letters can take up to 90 business days. You'll get an amended notice of assessment showing the updated result.
If you'll owe more
If the change means you owe more tax, the ATO treats your amendment as a voluntary disclosure. That's a good thing to do. The amendment itself (online, on the paper form, or by letter) is the approved way to tell them.
If more than two years have passed
Once the time limit has passed, an amendment usually isn't possible. You may be able to lodge an objection instead, and in some cases ask for more time. The ATO explains this on its objections pages, and an accountant can help.
How NestWise helps
When you mark a tax year as lodged in NestWise, it's locked, so nothing changes by accident. It keeps who lodged it and the day it was lodged, and shows how long you can usually still change it. If you need to amend, choose Reopen to make a change on that year's Finalise page. Add the missed deduction or fix the figure, lodge the change on myGov or through your accountant, then mark it lodged again. NestWise keeps the original lodged day and adds the day of the change.
Source: the ATO's "Amend your tax return" pages (before you amend, how to request an amendment, and time limits on amendments), read 5 November 2026.