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How self-assessment affects you

Self-assessment means we use the information you give on your tax return to work out your refund or tax liability.

Last updated 11 June 2017

In addition to this, we also use the information you give on any related schedules and forms to work out your refund or tax liability. We do not take any responsibility for checking the accuracy of the details you provide, although our system automatically checks the arithmetic.

Although we do not check the accuracy of your tax return at the time of processing, at a later date we may examine the details more thoroughly by reviewing specific parts, or by conducting an audit of your tax affairs. We also have a number of audit programs that are designed to continually check for missing, inaccurate or incomplete information.

What are your responsibilities?

It is your responsibility to lodge a tax return that is signed, complete and correct. Even if someone else, including a tax agent, helps you to prepare your tax return and any related schedules, you are still legally responsible for the accuracy of your information.

What if you lodge an incorrect tax return?

If you become aware that your tax return is incorrect, you must contact us straight away.

Initiatives to complement self-assessment

There are a number of systems and entitlements that complement self-assessment, including:

  • the private ruling system
  • the amendment system (if you find you have left something out of your tax return)
  • your entitlement to interest on early payment or over-payment of a tax debt.

Do you need to ask for a private ruling?

If you are uncertain about how a tax law applies to your personal tax affairs, you can ask for a private ruling. To do this, complete a Private ruling application form (not for tax professionals), or contact us.

Lodge your tax return by the due date, even if you are waiting for a response to your application. You may need to request an amendment to your tax return once you have received the private ruling.

We publish all private rulings at

Before we publish them we edit the text to remove any information that would identify you.