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About GST adjustments

Found out about the meaning of and types of GST adjustments.

Published 14 September 2026

How GST adjustments work

You may have to make changes on your current BAS to increase or decrease the amount of GST you must pay for a reporting period. These changes are known as 'adjustments'.

There are two types of adjustments:

  • increasing adjustments, which increase how much GST you must pay for a reporting period
  • decreasing adjustments, which decrease how much GST you must pay for a reporting period.

Making GST adjustments is different from correcting GST errors made on an earlier activity statement. A GST adjustment relates to a reported sale or purchase that was correct at the time of lodgment, whereas a GST error relates to an amount that was incorrect at the time of lodgment.

Example: adjustment due to refunded sales

Johnny K Entertainment intends to hold a concert in April. In February, they sell 2,000 tickets for $110 each including GST. They remit the $20,000 GST in their February monthly activity statement.

In March, they cancel the concert and refund all ticket holders $110 each. In their March activity statement, they include a decreasing adjustment of $20,000 (one-eleventh of the refunded amount).

End of example

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