What Is an Income Tax Assessment? How the ATO Calculates Your Tax Outcome

An Income Tax Assessment is the ATO’s formal calculation of your tax payable or refundable based on the information you lodge in your tax return.

Once the ATO processes your return, it issues an Income Tax Assessment Notice (commonly part of your Notice of Assessment) detailing how much tax you owe — or how much you’ll get back.

What the Income Tax Assessment Shows

• Taxable income
• Total tax payable
• Credits and offsets applied
• Amount of tax withheld (e.g. PAYG)
• Final balance: tax due, refund, or zero
• Medicare levy and surcharge (if applicable)
• Any prior year balances or interest charges

This assessment is the ATO’s final say on your return — unless you amend or dispute it.

How It’s Issued

Method of Lodgement	How You Receive Assessment
Through myGov	Via myGov inbox
Through a tax agent	Your agent receives it electronically
Paper return	Posted to your nominated address

Processing usually takes 2–14 days for electronic returns.

What to Do When You Receive It

1. Review the income, deductions, and credits
2. Check the net result (refund, payable, nil)
3. If refund: ATO will transfer it to your bank
4. If payable: Make payment by due date (on notice)
5. If there’s an error: request an amendment or objection

Always keep a copy for at least five years.

Assessment vs Notice of Assessment

Term	Meaning
Income Tax Assessment	The ATO’s calculation of your tax
Notice of Assessment	The document that shows the assessment

You’ll often hear both terms used interchangeably — but the assessment is the process, and the notice is the output.

How Ozobooks Helps

• Reviews your assessment line by line
• Explains complex ATO calculations (e.g. offsets, levies)
• Prepares amendments if something’s incorrect
• Communicates with ATO on your behalf
• Helps plan for next year’s tax based on your outcome

FAQ

Q1: Do I always get an income tax assessment?
Yes — if you lodge a tax return, the ATO will issue an assessment, even if there’s nothing to pay.

Q2: Can the ATO amend my assessment?
Yes — the ATO can review or amend assessments within 2–4 years, depending on your circumstances.

Q3: What if I can’t pay the tax owed?
You can set up a payment plan with the ATO or get help through your tax agent.

Q4: Is the assessment always final?
Not always — you can dispute it through formal objection or request a correction.