BAS explained: What it is and how to lodge it

If you're a business owner, you've probably heard the term 'business activity statement' (or BAS) before. And with EOFY coming up, understanding your BAS obligations is more important than ever.

In today's article, we'll explain what BAS is, how and when to submit it, and what happens if you miss a deadline. Let's dive in.

What is BAS?

BAS is a form that businesses registered for GST need to lodge with the Australian Taxation Office (ATO) one to 12 times a year (depending on the size of their business).

This form is used to report and pay tax liabilities, such as [1]:

• Goods and services tax (GST)
• Pay as you go (PAYG) withholding
• PAYG instalments
• Fringe benefits tax (FBT) instalments
• Luxury car tax
• Wine equalisation tax
• Fuel tax credits

Businesses must register for GST if their annual turnover is $75,000 or over ($150,000 for not-for-profits). Once registered, you're required to lodge a BAS regularly, even if you have no GST to report for a period.

Keep in mind, as well, that lodging and paying your BAS are two separate obligations.

Even if you can’t pay by the due date, you still have to submit the statement on time to avoid penalties (more on this in a bit).

How do I lodge my BAS?

There are three ways to lodge your BAS: online, through a registered tax or BAS agent, or by mail [3].

Online

Lodging your BAS online is quick, convenient, and secure. You may get two additional weeks to complete it, can review your form before submitting it, and may even get a faster refund.

You can lodge your BAS electronically via:

• ATO online services for businesses
• Your myGov account (linked to the ATO), if you're a sole trader
• Online accounting software

Through an agent

If you have a registered tax or BAS agent, they can prepare and submit the statement for you.

This means they have access to your BAS, as well as any reminder messages through the online service they use.

You'll still retain access through online services for business or myGov, even when an agent lodges on your behalf.

It's also worth mentioning that using an agent means you may be eligible for an automatic extension beyond the standard BAS due dates, giving you more time to meet your obligations.

By mail

Although the ATO encourages business owners to choose the online method—and paper BAS forms are being phased out—lodging via mail is still an option.

In this case, you fill in the form manually and mail it to the ATO using the provided, pre-addressed envelope.

'nil' BAS

If you have nothing to report and need to lodge your BAS as 'nil,' you can do so online or over the phone.

When is BAS due?

As we mentioned before, how often you need to lodge this statement will depend on how big your business is—and more specifically, on your GST turnover (meaning your gross income minus GST) [2].

If you have an annual turnover of over $20 million, you must lodge monthly by the 21st of the following month. This means you need to submit your January BAS by 21 February, February BAS by 21 March, and so on.

If you have an annual turnover of less than $20 million, you must lodge quarterly (unless you've been told otherwise by the ATO). This is the most common case for small businesses, and the deadlines are as follows:

• Q1 (July, August, and September) - 28 October
• Q2 (October, November, and December) - 28 February
• Q3 (January, February, and March) - 28 April
• Q4 (April, May, and June) - 28 July

If you have an annual turnover of less than $75,000 (or $150,000 for not-for-profits) and are voluntarily registered for GST, you can lodge annually with your income tax return.

What happens if I miss my due date?

Missing the deadlines above can result in 'failure to lodge' (FTL) penalties, which are calculated based on the size of your business and how long it has been since the deadline [4].

For small businesses, the penalty is one unit ($313 as of 2025) for every 28 days (or part thereof) that the BAS is overdue, up to a maximum of 5 penalty units.

For medium businesses, the penalty unit is doubled, and for large entities, it is multiplied by 5.

It's important to mention that the ATO takes each business's circumstances into account and typically doesn't apply penalties in isolated cases of late lodgement.

You may get a warning by phone or in writing first, and if you do end up receiving an FLT penalty, it will specify the reason for it, the amount to be paid, and the due date for payment.

EOFY and tax season can be a great time to level up your business. If you want to do so without draining your cash flow, Valiant offers a wide range of asset financing solutions to suit your needs. Receive free, tailored quotes in less than two minutes.

{{first-banner}}

Want to save time and avoid costly mistakes? Our No-Nonsense Guide to GST & BAS for Small Businesses gives you everything you need to know in one quick download.

FAQs

What happens if I lodge a 'nil' BAS?

Lodging a ‘nil’ BAS simply tells the ATO you had no sales, purchases, wages, or other activity to report for that period. You still need to lodge it by the due date to avoid late penalties. If you've been making 'nil' BAS lodgments for a while and don’t expect your activity to pick up, you may want to consider cancelling your GST registration to simplify your reporting [5].

How do I correct a mistake in a BAS I already lodged?

You can correct a mistake in an already-lodged BAS either by making an adjustment in your next BAS (if it's a minor GST and fuel tax credit error) or by lodging a revised BAS (for larger mistakes) [6].

Do I need to keep records for my BAS? And for how long?

The ATO requires you to keep BAS-related records for at least 5 years [7].