Revising a BAS¶

Sometimes you find a mistake after you have already lodged a BAS — a sale you missed, a purchase entered twice, or a figure typed in wrong. You do not tear up the old one. Instead, you lodge a revision of that original statement, which tells the Australian Taxation Office (ATO) the correct figures for that period.

A revision is not a brand-new BAS for a new period. It replaces the figures on the statement you already lodged, so the ATO ends up with the right numbers for that time.

In one line

If you find an error in a BAS you have already lodged, you lodge a revision of that original statement — it updates what you owe or are owed for that period.

Why this matters¶

The figures on your BAS decide how much you pay the ATO or how much they pay you. If a figure was wrong, the amount was wrong too. Revising fixes the record for that period, so you are not left owing more than you should — or missing out on money owed to you.

What you will learn¶

What it means to revise a BAS you have already lodged
The difference between revising the original period and correcting the mistake on your next BAS
That a revision updates what you owe or are owed for that period

Understanding the concept¶

A revision is a corrected version of a BAS you have already lodged. You go back to that period, enter the right figures, and lodge it again. The ATO then treats the revised figures as the correct ones for that period.

The ATO describes two ways to fix a mistake from an earlier BAS:

Revise the original BAS. You correct the period the mistake was in. This is what you do when the mistake cannot be fixed on your next statement.
Correct it on your next BAS. For many smaller GST mistakes, the ATO lets you fix them on your next statement instead of revising the original one, as long as certain conditions are met.

Which path applies depends on the type and size of the mistake. A later Corrections lesson covers those rules in detail. The key point here is that both paths end in the same place — the ATO has the right figures — but a revision changes the original period, while a next-BAS correction rolls the fix into a later period.

Either way, fixing the figures changes the money. If the mistake meant you underpaid, the revision increases what you owe for that period. If it meant you overpaid, the revision reduces what you owe, or means the ATO owes you.

The ATO also sets a time limit for revising a BAS. In most cases you have four years to revise a statement, so it is best to fix mistakes as soon as you spot them.

For accountants & bookkeepers

Through ATO online services, a lodged statement shows a Revise option in the History tab where a revision is available. You edit the relevant labels, enter the corrected values and lodge. Whether a client should revise the original period or correct on the next BAS turns on the ATO's credit-error and debit-error conditions and the value limits that apply — covered in the Corrections lesson. The four-year period of review generally limits how far back a statement can be revised.

Example¶

Priya runs a small florist and lodges her BAS each quarter. A month after lodging, she realises she left a $2,200 wedding order out of her sales for the quarter. Because that sale included GST she collected, her original BAS understated the GST she owed.

Priya goes back to that quarter's statement and lodges a revision with the sale included. The revised figures show she owes a bit more GST for that period than her first statement did. She now has the right figures on record, and she pays the extra amount that the revision works out.

Her friend Jordan had the opposite problem — he accidentally entered a large equipment purchase twice, which overstated his GST credits. His revision reduces his credits for that period, correcting the record the other way.

Common mistakes¶

Thinking you must lodge a whole new BAS — you revise the original statement instead.
Assuming every mistake has to go back to the original period — many smaller GST mistakes can be fixed on your next BAS instead.
Leaving a known error unfixed — a revision updates what you owe or are owed, so it is better to correct it than ignore it.
Forgetting there is a time limit — in most cases you have four years to revise.

How this works in myaccountant¶

In the app — myaccountant lets you revise a statement you have already lodged. You open the period, correct the figures, and lodge the revision, and the app shows the updated outcome for that period — whether you now owe more, owe less, or are owed a refund.

Key points¶

A revision is a corrected version of a BAS you have already lodged.
You can revise the original period, or fix many smaller GST mistakes on your next BAS.
A revision replaces the figures for that period, not for a new period.
Fixing the figures updates what you owe or are owed for that period.
In most cases you have four years to revise a statement.
Fix mistakes as soon as you find them.

Learn next¶

General information only — not tax, super or financial advice.

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