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Fixing BAS mistakes or making adjustments

What to do if you need to fix a mistake in a previously lodged BAS or make an adjustment for a change.

Last updated 18 July 2023

What are mistakes or adjustments

Correcting a mistake made in an earlier business activity statement (BAS) is different to making an adjustment:

  • An error or mistake relates to an amount that was incorrect at the time of lodgment.
  • An adjustment relates to a reported sale or purchase that was correct at the time of lodgment, but something occurred later that changed the amount of reported GST.

When to fix a mistake

Examples of mistakes you may have made in a previously lodged BAS include:

  • clerical or transposition errors
  • classifying a GST-free sale or purchase as taxable
  • classifying a taxable sale or purchase as GST-free
  • double counting some of your purchases.

How to fix a mistake

You can fix a mistake in your next BAS or revise the original BAS. Conditions apply depending on whether it's a credit error or debit error.

Many mistakes relating to GST and fuel tax credits can be corrected in your next BAS. If you can't correct your mistake in your next BAS, you will need to lodge a revision.

Corrections that impact PAYG withholding

If you are an employer and you need to fix your STP reporting, you may also identify that the PAYG withholding you reported to us for a previous tax period was too high or too low. To correct this, you can either:

  • Revise an earlier activity statement for the earlier tax period to show the correct amount. For large withholders, follow the existing process for notifying us of changes to your PAYG withholding liability in an earlier tax period.
  • Carry forward the correction to your reported PAYG withholding for the current tax period, subject to some limits. See Correcting information reported through STP.

When to make an adjustment

When you become aware of the need for an adjustment, you generally report it in the activity statement for your current reporting period.

Examples of when to make an adjustment include where:

  • the price of a sale or purchase changes
  • goods are returned and the sale is cancelled.

For fuel tax credits, see Making adjustments and correcting errors.

How to lodge your changes

You can lodge your changes online or by paper form:

Your registered tax or BAS agentExternal Link can assist via Online services for agents.