How to Amend an Australian Tax Return — myTax Guide 2025-26

Who This Guide Is For

TL;DR — You can amend an Australian tax return through myTax for up to 2 years after your original Notice of Assessment was issued (4 years for some specific items). The process takes 10–20 minutes online and the ATO (ATO guidelines) usually processes the amendment within 20 business days. There's no penalty for honest amendments you initiate yourself, but interest may apply if you're paying additional tax.

This guide is for anyone who lodged a tax return and later realised something was wrong — missing income, forgotten deductions, or an error in the figures. Whether you under-claimed and want a bigger refund, or over-claimed and want to fix it before the ATO does, the steps are the same. (Haven't lodged yet? Start with our step-by-step myTax guide.)

When You Can Amend

Direct answer: Most individuals have 2 years from the date of their Notice of Assessment (NoA) to amend a tax return. Some specific items get 4 years (small business, complex investments). Beyond those windows you can still correct errors via a formal Objection, but it's a different process.

For FY2025-26 (lodged after 1 July 2026, NoA typically issued by mid-July 2026):

• Standard amendment window: closes around mid-July 2028
• 4-year window for eligible items: closes around mid-July 2030
• After that: Objection only, with stricter rules

Important: The 2-year clock starts from the NoA date, not the lodgement date or the financial year end. Check your NoA email or PDF for the exact date.

When You Should Amend

Common reasons to amend:

• Missed income — a forgotten bank account interest, late-arriving employer income statement, dividend you didn't realise was taxable
• Forgotten deduction — work-from-home hours you didn't track at lodgement, a tool purchase you remembered later, a charity donation receipt you found in a drawer
• Wrong figure — entered $5,000 instead of $50,000 for income, transposed digits in a deduction
• Wrong residency status — you ticked non-resident when you should have been a tax resident
• Wrong Medicare Levy section — you forgot to claim an exemption (international students are common cases)
• Spouse details correction — Family Tax Benefit / offset eligibility recalculated
• HECS/HELP indicator — turned on or off in error

If the change is because of a Notice from the ATO (audit, query, or amendment notice), follow their specific process — don't lodge an amendment unprompted while you're already in their queue.

Before You Amend

Gather:

• Your original lodgement summary or NoA (in your myGov inbox)
• The new evidence supporting the change (receipt, statement, MES, etc.)
• Your bank account details (in case the result is a refund, or a refund deposit needs verification)
• Approximately how much extra tax you'll owe or refund you'll receive — use the free FY2025-26 calculator to estimate before you commit

Step-by-Step: Amending via myTax

Step 1: Sign in to myGov and open the ATO

Go to my.gov.au → click Australian Taxation Office → choose Tax → Lodgments → Income tax.

You'll see a list of all your lodged returns. Each has a status (e.g. "Assessed").

Step 2: Open the year you want to amend

Click the financial year (e.g. 2025-26 or earlier). Inside, you'll see options including History, Notice of assessment, and Amend.

Click Amend.

Step 3: Make your changes

myTax loads your original return with all the numbers pre-populated. Don't start over — only change the sections that need correction.

• For missed income: scroll to the relevant section (e.g. Interest, Dividends, Salary), click Edit or Add, enter the new details
• For forgotten deductions: scroll to the deductions section, click Add, enter the amount and supporting note
• For corrections: change the relevant figures in place

The page recalculates as you go, showing the new tax position vs the original.

Step 4: Provide the reason

myTax requires a brief explanation of why you're amending. Be honest and specific:

• Good: "Forgot to claim work-from-home hours; 800 hours × 70¢ = $560 deduction"
• Good: "Bank account 12345678 paid $124 interest in FY2025-26 not previously declared"
• Bad: "Update" (too vague — may delay processing)

Step 5: Review the amended summary

myTax shows a comparison: original vs amended figures. The bottom line will show:

• Additional refund — paid to your bank account
• Additional amount payable — due by a date shown on the amended NoA
• Net interest — small interest amount may apply if you're paying more tax (calculated from when the original tax was due to when you pay)

Step 6: Lodge the amendment

Click Lodge amendment. You'll get a confirmation email. The ATO usually processes amendments within 20 business days — sometimes faster.

You'll receive an amended Notice of Assessment showing the new final figures.

What If You Owe More Tax After Amending

If the amendment shows you owe more tax (under-declared income, over-claimed deduction):

If the additional debt creates hardship, you can request a payment arrangement through the ATO portal.

What If the Result Is a Bigger Refund

The additional refund deposits to the bank account on file with the ATO. If your account changed:

Refund processing for amendments takes about the same as a fresh lodgement: 2 weeks for straightforward cases, longer if reviewed.

Beyond the 2-Year Window: Filing an Objection

If your amendment window has closed, you can still correct errors by filing a formal Objection to your assessment. This is more complex:

• Submit a written or online Objection through the ATO portal
• Include the specific items you want changed and supporting evidence
• The ATO has 60 days to respond; complex cases longer
• If you disagree with the Objection decision, you can escalate to the Administrative Appeals Tribunal (AAT)

For most people, an Objection is overkill. It's typically used when:

• A significant amount is at stake ($1,000+)
• You've discovered evidence years after the fact (e.g. a missed tax-deductible expense from 5 years ago, supported by paperwork)
• The ATO has refused an earlier amendment

Consider engaging a registered tax agent for an Objection — the process is more legalistic.

Common Amendment Scenarios

Scenario 1: Missed work-from-home hours

You worked 700 hours from home but only claimed 200 at lodgement. Now you find your hour log.

Fix: Amend → deductions → work-from-home → change hours. With FY2025-26 fixed rate at 70¢/hr, additional 500 hours × 70¢ = $350 extra deduction. At 30% marginal rate, that's about $105 more refund.

Scenario 2: Forgotten Medicare Levy exemption

International student forgot to claim the Medicare Levy exemption. They've now received their Medicare Entitlement Statement.

Fix: Amend → Medicare Levy section → claim exemption → attach MES details. On $40,000 income, refund increases by 2% × $40,000 = $800.

Scenario 3: Late dividend statement

A share registry sent your dividend statement after you lodged. You realise you missed $400 of franked dividends + $171 franking credit.

Fix: Amend → income → dividends → add the new entry. Net effect depends on your bracket — franking credits may even result in a net refund increase.

Scenario 4: Over-claimed travel

You claimed 5,000 km vehicle costs but realise your actual work travel was 2,000 km without proper records.

Fix: Amend → deductions → vehicle → reduce to 2,000 km. You'll owe back the difference. Self-correcting now is much better than the ATO finding it during an audit (penalties apply in that case).

Records to Keep

Records for the amended return must be kept for 5 years from the amendment date, separately from the original 5-year window. Common items:

• Original NoA
• Amended NoA
• Email confirmations of lodgement and amendment
• Receipts and supporting documents for any newly-claimed deduction
• The MES if you added a Medicare Levy exemption

If the same evidence supports both the original and amended return, keep it for the later of the two 5-year windows.

Common Mistakes When Amending

When to Use a Tax Agent for Amendment

DIY through myTax is fine for:

• Single missed income item or deduction
• Clear-cut Medicare Levy or HECS toggle
• Numerical typo correction

Consider a registered tax agent if:

• The amendment is for an Objection beyond the 2-year window
• The change involves capital gains, business income, or property
• The ATO has already initiated a review
• Multiple years are affected (e.g. missing rental income for 3 years running)

Tax agent fees for an amendment are typically $100–$300 and are deductible the following year.

Quick Checklist — Before Lodging an Amendment

• Original Notice of Assessment found and reviewed
• New evidence (receipts, statements, MES) gathered
• Within 2-year amendment window from NoA date
• Estimated impact on refund/owing calculated
• Specific reason for amendment drafted
• Bank account on file is current (for refund or contact)
• Original return found in myTax (don't lodge a new one)
• Amended figures reviewed before clicking Lodge

Need Help With Your Tax Return?

Complex situation? a registered tax agent (see the directory) Our partner agents review every detail for accuracy and compliance.

*Disclaimer: This guide provides general information about amending an Australian tax return. It is not personal tax advice. For complex situations, including Objections and ATO review responses, consult a registered tax agent. AusTax AI is not a registered tax agent — our complete service connects you with TPB Registered Tax Agents.*