The "something's wrong with my BAS" checklist¶

When an Activity Statement (your BAS) throws up a warning, a number that looks odd, or a figure that will not match, it is easy to feel stuck. The good news is that almost every BAS problem is found by working through the same short list of checks, in order.

This lesson is that list. Take one step at a time. Most issues turn out to be a simple mismatch — a wrong date, a figure typed in the wrong box, or a period that does not line up — and each one is fixable.

Why this matters¶

A BAS reports real money to the Australian Taxation Office (the ATO) — what you collected in GST, what you withheld from wages, and what you owe or are owed. Rushing to "just make it go through" can lock in a wrong number. Working the checklist slowly means you fix the real cause once, rather than guessing and creating a second problem.

What you will learn¶

• How to work through a BAS problem in a calm, ordered way
• How to check your figures, period, pre-fill and payment against your own records
• When to fix the mistake in your next BAS, revise it, or contact the ATO or your agent

Understanding the concept¶

Here is the checklist. Read the warning first, then work down. Stop as soon as you find the cause — you rarely need every step.

1. Read the flag or error, word for word. Before changing anything, read exactly what the screen is telling you. Is it a warning you can pass, or an error that blocks lodgment? Note any label it names, such as G1 (total sales) or W2 (amounts withheld). The message usually points straight at the box that needs attention.

2. Check your figures against your own records. Open your books for the period and compare them to the amounts on the BAS. Do your total sales, your GST, and your wages match what your accounts say? A single figure typed into the wrong box, or a sale left out, is the most common cause. The ATO says your own software and records should be your primary source — trust them over any number that appears pre-filled.

3. Check the reporting period. Confirm the BAS covers the dates you think it does. A figure that looks "wrong" is often right for a different quarter. Make sure you are looking at the correct period, and that a transaction has not landed just inside or just outside the dates.

4. Check the pre-fill against your payroll. If you pay wages, the ATO pre-fills the PAYG withholding labels W1 and W2 from your Single Touch Payroll (STP) reports. If those do not match your payroll, the usual cause is an STP report that was missed, sent late, or sent with the wrong figures. The ATO says you should feel confident to correct the pre-fill to match your records — your payroll is the source of truth, not the pre-fill.

5. Check the payment reference and timing. If your payment has not shown up against the BAS, check that you used the correct payment reference number for this statement, and that you paid to the right BPAY or account details. Payments matched to the wrong reference, or made after a cut-off, can look "missing" when they are simply sitting elsewhere.

6. Decide how to fix it. Once you know the cause:

• If you have not lodged yet, correct the figure on the BAS and lodge.
• If you have already lodged and the mistake is small, the ATO says many GST mistakes can be corrected in your next BAS.
• If you cannot correct it in the next BAS, you revise the original statement.
• If you are unsure, or the amounts are large, contact the ATO or a registered tax or BAS agent before you act.

7. Know when to get help. If a step above does not clear the problem, or you are not sure which fix applies, that is the moment to ask — not later. You can contact the ATO, or a registered tax or BAS agent, who can lodge, revise and pay on your behalf.

Example¶

Priya runs a small cafe in Adelaide and lodges her BAS each quarter. This quarter the screen flags that her PAYG withholding does not match. She stays calm and works the checklist.

Step 1 — read the flag. It names the withholding labels, W1 and W2. So the issue is wages, not sales.

Step 2 — check her figures. Her payroll records show she paid three staff all quarter.

Step 3 — check the period. The dates are correct — the current quarter.

Step 4 — check the pre-fill against payroll. Here she finds it. The pre-filled W2 is lower than her payroll. She realises one pay run's STP report was never sent to the ATO, so that pay is missing from the pre-fill. She corrects the W1 and W2 figures on the BAS to match her own payroll records, as the ATO says she should, and makes a note to send the missing STP report.

Priya did not need steps 5, 6 or 7. She found the cause at step 4, fixed the figures to match her records, and lodged with confidence.

Common mistakes¶

• Changing a figure before reading what the flag actually says.
• Trusting the pre-filled number over your own payroll or books.
• Looking at the wrong reporting period and "fixing" a figure that was already correct.
• Assuming a payment is lost when it was sent with the wrong reference number.
• Waiting until after the due date to ask for help, instead of contacting the ATO early.

How this works in myaccountant¶

Key points¶

• Work the checklist in order and stop as soon as you find the cause.
• Read the flag first; it usually names the label that needs attention.
• Your own books and payroll are the source of truth — correct the pre-fill to match them.
• Check the reporting period before you decide a figure is wrong.
• Fix small mistakes in your next BAS; revise the original where you cannot.
• Ask the ATO or a registered agent early if you are unsure.

Learn next¶

• When your Activity Statement shows a validation error
• When a payment does not match your Activity Statement
• Activity Statement questions, answered

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