A BAS deadline can arrive quickly when you are managing customers, suppliers, payroll and the day-to-day work of running a business. If you are asking when is BAS due, the answer depends on whether you report monthly, quarterly or annually. Your activity statement or online ATO account will show the due date that applies to your business, but knowing the usual dates makes planning far less stressful.
For most small businesses registered for GST, BAS is lodged quarterly. It is used to report and pay GST, PAYG withholding, PAYG instalments and other obligations that may apply to your business. Not every BAS includes every label, so it is worth checking what is actually required before lodging.
When is BAS due for quarterly reporters?
Quarterly BAS reporting is the most common arrangement for small and medium-sized businesses. The standard due dates are based on the end of each quarter:
| Quarter | Period covered | Standard BAS due date | | — | — | — | | Quarter 1 | 1 July to 30 September | 28 October | | Quarter 2 | 1 October to 31 December | 28 February | | Quarter 3 | 1 January to 31 March | 28 April | | Quarter 4 | 1 April to 30 June | 28 July |
These dates generally apply to both lodgement and payment. In other words, if your BAS shows an amount owing, the ATO normally needs to receive the BAS and the payment by the relevant due date.
There are a few practical exceptions. If the due date falls on a weekend or public holiday, the next business day is usually accepted. Businesses that use a registered BAS or tax agent may also be eligible for different lodgement arrangements under the ATO’s agent lodgement program. Those arrangements are not automatic in every circumstance, so it is sensible to confirm the date shown in your ATO account or with your agent rather than relying on a general extension.
Monthly BAS due dates
Businesses that report monthly usually need to lodge and pay their BAS by the 21st day of the following month. For example, a BAS for July is generally due on 21 August.
The main exception is the December activity statement. The December monthly BAS is generally due on 21 February, giving businesses some breathing room over the Christmas and New Year period.
Monthly GST reporting is generally required once GST turnover reaches $20 million or more. Some businesses below that threshold choose monthly reporting because it can provide more regular GST refunds and a closer view of cash flow. The trade-off is more frequent bookkeeping and less time to resolve missing invoices or coding errors.
Annual GST reporting and BAS timing
Some eligible small businesses can report GST annually instead of quarterly. This is not available to every business, and eligibility depends on factors including GST turnover and whether you have chosen annual reporting with the ATO.
An annual GST return is generally due at the same time as your income tax return. If you do not need to lodge an income tax return, the annual GST return is generally due by 28 February following the end of the financial year. Because annual arrangements can differ from business to business, always use the due date printed on your activity statement as the final reference point.
BAS due dates are not the only dates to manage
A common source of confusion is assuming that every tax obligation follows the BAS cycle. Your activity statement may include GST, PAYG withholding from employee wages and PAYG instalments, but other obligations have their own reporting and payment requirements.
For example, payroll-related obligations need careful attention throughout the year. Single Touch Payroll reporting is submitted when you pay employees, while superannuation guarantee payments have separate quarterly deadlines. Your income tax return is also a separate annual obligation. Keeping a simple compliance calendar helps ensure one deadline is not missed while you are focused on another.
If you receive an instalment activity statement rather than a BAS, you may be reporting PAYG instalments without GST. The due dates can look similar, but the information you need to prepare is different. Reading the form and labels carefully matters.
What you need before lodging BAS
The best way to make BAS lodgement straightforward is to avoid leaving the records until the week it is due. Your BAS figures should come from up-to-date bookkeeping, not a hurried estimate based on the bank balance.
Before you lodge, make sure sales and expense transactions are entered and correctly coded, bank accounts are reconciled, and tax invoices are available for GST claims. Review any large or unusual transactions, including asset purchases, deposits, insurance proceeds and private expenses paid from the business account. These can affect the GST treatment and should not be guessed.
If you employ staff, reconcile wages, PAYG withholding and payroll reports against the amounts being reported. For businesses using accounting software, the BAS report is useful, but it is not a substitute for checking whether the underlying transactions have been recorded correctly. Software can calculate from the data it has been given. It cannot identify every missing invoice, duplicated bill or incorrectly treated expense.
What happens if you lodge or pay late?
Missing a BAS due date can create unnecessary pressure. The ATO may apply a failure to lodge penalty, and interest may accrue on overdue amounts. The outcome depends on the size and circumstances of the business, the delay involved and your broader compliance history.
If you cannot pay the full amount by the due date, lodging the BAS on time is still usually the better approach. It gives the ATO an accurate picture of what is owed and may allow you to discuss a payment arrangement. Waiting to lodge because payment is difficult can increase the risk of penalties and make the issue harder to manage.
The same principle applies when you believe a BAS contains an error. Do not ignore it. In many cases, an error can be corrected through a later BAS or by revising the original statement, depending on the type and size of the error. The appropriate approach depends on the facts, so get advice before making a correction that could affect GST, payroll withholding or cash flow.
A simple way to stay ahead of BAS deadlines
Set aside time each week or fortnight to process transactions, upload receipts and reconcile accounts. That rhythm is usually easier than tackling three months of records at once. It also gives you a more useful picture of profitability and upcoming tax commitments while there is still time to act.
For quarterly reporters, aim to have your records ready shortly after the quarter ends, rather than on the 28th. This leaves room to chase invoices, review unexpected figures and set aside funds for any amount owing. If your cash flow changes significantly through the year, regular reporting can also help you make more informed decisions about stock, staffing and major purchases.
A registered BAS or tax agent can prepare and lodge on your behalf, but the business owner still benefits from supplying complete records promptly. At Hire An Accountant, the focus is on turning BAS requirements into clear, practical next steps, so you know what is due, what the figures mean and what needs attention before lodgement.
A due date should be a prompt to review your numbers, not a last-minute emergency. With current records and a clear routine, BAS lodgement becomes one more manageable part of running your business.
