Who can prepare and lodge a BAS?

A business can prepare and lodge its own. To do it for a fee on someone else behalf, you must be a registered BAS agent or tax agent. That includes advising on GST or PAYG obligations, not just pressing lodge. If you are unsure, check with the Tax Practitioners Board.

Most small businesses lodge quarterly, generally by the 28th of the month after quarter end, with an extra two weeks available when lodging through a registered agent. The December quarter usually gets a longer period. Businesses with GST turnover of $20 million or more lodge monthly, and some small businesses lodge annually. Confirm the current due dates rather than relying on a remembered one.

What is the difference between cash and accruals GST?

On a cash basis you account for GST when money changes hands. On accruals you account for it when the invoice is issued or received. It changes which transactions belong in which period, so confirm the basis before you start — it is the first check on this list for that reason.

What is the most common BAS error?

Claiming GST credits where none exist — bank fees, interest, council rates and wages are the usual suspects, because all four look like normal business expenses and none of them carry GST. The second most common is reporting a capital purchase at G11 instead of G10. That rarely changes the GST claimed but it does misreport the statement.

Do I need a tax invoice for everything?

To claim a GST credit you generally need a valid tax invoice, unless the purchase was $82.50 including GST or less. For those you still need a record of what it was and that it was for the business. The checklist includes a step to confirm invoices are on file for purchases above that threshold.

What if I find an error in a BAS I already lodged?

Small errors can often be corrected on a later BAS rather than by revising the original. There are limits based on the size of the error and your turnover, and on how far back you can go. Check the current correction limits, and document what you corrected and why.

What working papers should I keep?

Whatever supports the figures you lodged — the reconciliations, the GST control account movement, the payroll reports supporting W1 and W2, and the lodgement receipt. Keep them for five years. If a BAS is ever queried, working papers are the difference between a short conversation and a reconstruction.

Should I reconcile before or after preparing the BAS?

Before, always. A BAS built on unreconciled books is a BAS you will probably revise, and revising is more work than reconciling was. The checklist is deliberately ordered so reconciliation sits at stage two and figure preparation at stage five.

FREE EXCEL CHECKLIST Last updated 28 August 2026

BAS preparation checklist for bookkeepers and BAS agents

Thirty-nine checks in the order that saves time — reconcile, then review coding, then prepare the figures, then lodge. Built to be worked through a client file rather than read once and forgotten.

BAS preparation checklist

Excel (.xlsx) · 39 checks · no signup

39 checks across 6 stages

Tick, owner, date and notes columns

GST coding traps called out

Payroll and STP checks included

General information only, not tax or accounting advice.

This template is general information for Australian businesses. GST treatment, account coding, reporting obligations and deduction eligibility depend on your circumstances — confirm them with your accountant, a registered BAS agent or the ATO. It does not constitute legal, HR, or professional advice and should not be relied on as a substitute for advice specific to your business, workforce, or circumstances.

References HR Hub disclaimer Modern Awards Fair Work

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What's in the BAS checklist

Six stages, worked top to bottom.

1. Before you start

Cycle, due date, cash or accruals basis, who is authorised to lodge, and whether any prior period needs correcting.

2. Reconcile

Every bank account, credit cards, petty cash and merchant settlements. Nothing downstream is safe until this is done.

3. Review GST coding

Eight checks covering the codings that are actually wrong in most files — bank fees, rates, wages, capital purchases, overseas subscriptions.

4. Payroll figures

Gross wages to the ledger, PAYG withheld to W2, STP filed, superannuation on OTE and paid on time.

5. Prepare and check

G1, 1A and 1B, a period-on-period comparison, and the GST control account clearing to the net position.

6. Lodge and record

Client authorisation, lodgement, the BAS journal, the payment date, and working papers filed for five years.

The coding checks that find the most errors

These six account types are where GST is most often claimed when it should not be.

Check	Common error	Effect on the BAS
Bank fees	Coded GST	Overstates credits at 1B
Interest	Coded GST	Input taxed — no credit exists
Council rates	Coded GST	Overstates credits at 1B
Wages & super	Coded GST	Overstates credits at 1B
Capital purchases	Reported at G11	Misreports G10
Overseas subscriptions	Assumed GST-free	Depends on the supplier

All six overstate what you claim, which is the direction that attracts attention. Running these checks takes minutes and is the highest-value part of the whole review.

The order matters more than the checks

Working out of sequence means redoing work, every time.

Reconcile first

Reviewing coding on an unreconciled file means reviewing transactions that may change. Bank first, always.

Then coding

Once the transactions are settled, check how they were coded. This is where the real errors are.

Then the figures

G1, 1A and 1B fall out of correctly coded, reconciled data. Preparing them earlier just means preparing them twice.

Lodge last

With client authorisation recorded, and the BAS journal posted so the GST control account clears.

Who can lodge a BAS for a fee

Only a registered BAS agent or tax agent can charge a fee to prepare and lodge a BAS on someone else behalf, or to advise on GST and PAYG obligations. Working under supervision inside a business you are employed by is different from providing a BAS service for a fee.

If you are unsure whether what you are doing requires registration, check with the Tax Practitioners Board before you invoice for it.

Errors in an earlier BAS

Small errors can often be corrected on a later BAS rather than by revising the original, which is considerably less work. There are limits on the size of the error and how far back the concession reaches, and they depend on turnover.

Check the current correction limits before deciding which route to take, and keep a note of what you corrected and why.

Who uses a BAS checklist

Bookkeepers and BAS agents

A consistent process across a client book, so quality does not depend on who did it.

Businesses lodging their own

Most of the value is in the coding review, which is where self-lodged BAS most often goes wrong.

Anyone training a new starter

The checklist is the training. Hand it over and review the notes column.

For accountants & bookkeepers

Do you lodge BAS for shift-based businesses?

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Definitions

Plain-English explanations of the terms used on this page.

FAQ

BAS preparation questions

A business can prepare and lodge its own. To do it for a fee on someone else behalf, you must be a registered BAS agent or tax agent.

That includes advising on GST or PAYG obligations, not just pressing lodge. If you are unsure, check with the Tax Practitioners Board.
Most small businesses lodge quarterly, generally by the 28th of the month after quarter end, with an extra two weeks available when lodging through a registered agent. The December quarter usually gets a longer period.

Businesses with GST turnover of $20 million or more lodge monthly, and some small businesses lodge annually. Confirm the current due dates rather than relying on a remembered one.
On a cash basis you account for GST when money changes hands. On accruals you account for it when the invoice is issued or received.

It changes which transactions belong in which period, so confirm the basis before you start — it is the first check on this list for that reason.

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