What Is an Activity Statement? BAS vs IAS Guide for 2026–27

An activity statement is the form Australian businesses use to report and pay GST, PAYG withholding, PAYG instalments and some other taxes to the Australian Taxation Office (ATO). GST-registered businesses lodge a Business Activity Statement (BAS); if you aren't registered for GST but withhold tax from wages or pay PAYG instalments, you lodge an Instalment Activity Statement (IAS) instead. Most businesses lodge quarterly (due 28 October, 28 February, 28 April and 28 July), and you must lodge even when you have nothing to report. Think of it as your business’s regular ‘tax check-in’.

What You'll Learn

• What Is an Activity Statement in Plain English
• How to Read Your Business Activity Statement (BAS)
• Who Needs to Lodge an Activity Statement and When
• Navigating Lodgement Deadlines and Avoiding Penalties
• Your Step-by-Step Guide to Lodging Your Activity Statement

What Is an Activity Statement in Plain English

Let's cut through the confusing tax jargon for a moment.

Imagine your business is a small shop. Throughout the month, you collect a little extra on every sale for the government (that's the GST). At the same time, you set aside money from your employees' wages for their income tax (PAYG Withholding). An Activity Statement is simply the form you use to tell the ATO exactly how much you’ve collected and then pay it to them.

But it’s a two-way street. The form is also where you claim back the GST you paid on things you bought for your business, like new equipment or office supplies. This ensures you only hand over the net difference.

The Activity Statement is essentially the scorecard that keeps your business and the ATO on the same page. It reconciles the taxes you've collected on the government's behalf with the tax credits you're entitled to claim.

The Two Main Types of Activity Statements

While many people use the term "BAS" as a catch-all, there are actually two distinct forms you might receive from the ATO. Getting this right is the first step to staying compliant.

• Business Activity Statement (BAS): This is the one most businesses deal with. You'll use a BAS if your business is registered for Goods and Services Tax (GST). It’s an all-in-one form for reporting your GST, PAYG withholding for staff, PAYG instalments for your own income tax, and a few other tax obligations. You can get a deeper look at the fundamentals in our guide explaining what BAS is in accounting.
• Instalment Activity Statement (IAS): This is a much simpler version. You’ll receive an IAS if you are not registered for GST but still need to report other taxes to the ATO. This is common for businesses that need to remit PAYG withholding for employees or pay their own PAYG instalments to pre-pay income tax throughout the year.

Key Taxes Reported on Your Activity Statement

Here are the main taxes reported on a typical activity statement, and who they affect:

• GST: the GST you’ve collected on sales, less the GST credits on your business purchases. Applies to all GST-registered businesses (GST turnover of $75,000 or more, $150,000 for not-for-profits, or voluntary registration).
• PAYG withholding: the income tax you’ve withheld from employees' wages and certain other payments. Applies to any business with employees.
• PAYG instalments: advance payments of income tax on your business and investment income, so you don't face a large bill at tax time. Applies to sole traders, partners, companies, trusts and others the ATO has entered into the PAYG instalments system.
• FBT instalments: quarterly instalments of fringe benefits tax on benefits such as a work car available for private use. Applies to employers whose FBT liability for the previous FBT year was $3,000 or more.

Understanding these components is crucial because it directly impacts your business's cash flow and compliance. Missing one can lead to trouble down the road.

Why Is It So Important for Your Business

Your Activity Statement isn't just another bit of paperwork; it's a fundamental part of Australia's tax system. Introduced alongside the GST on 1 July 2000, the BAS has become the backbone of business tax compliance in Australia.

For the businesses we work with every day at Australia Wide Tax Solutions, lodging an Activity Statement correctly and on time is non-negotiable. It ensures you meet your legal obligations, helps you manage cash flow by giving you a clear picture of your tax liabilities, and—most importantly—prevents stressful and expensive penalties from the ATO for late or incorrect reporting.

How to Read Your Business Activity Statement (BAS)

Cracking open your first Business Activity Statement can feel intimidating. It often looks like a wall of codes, boxes, and tax jargon that makes little sense at first glance.

But once you know what you’re looking at, that jumble of numbers starts to tell a clear story about your business's financial health over the last quarter. Think of it less as a chore and more as a financial snapshot—a tool you can use to stay on top of your obligations.

Let's walk through it with a simple, real-world example. Imagine you’re a digital marketing consultant. Every time you invoice a client, you include GST. And every time you buy software or a new laptop for your business, you pay GST. The BAS is simply where these two sides of the coin meet.

The simple flow below sums it up: what happens in your business each quarter is reported to the ATO through your activity statement.

Decoding the GST Section

For most businesses, the heart of the BAS is the GST section. This is where you'll spend most of your time.

• G1 Total Sales: This is your starting point—your total sales for the period, including any GST (or, if you account for GST on a cash basis, the payments you received). It includes all your sales, whether they had GST on them or not. For our consultant, this would be the total of all their client invoices for the quarter.
• 1A GST on Sales: Here, you report only the GST component you collected on behalf of the ATO. If our consultant invoiced a total of $11,000 (all taxable sales), they would report $1,000 at 1A (which is 1/11th of the GST-inclusive total).
• 1B GST on Purchases: This is where you get your money back. You report the total GST you paid on business-related purchases and expenses. Think software subscriptions, fuel, office supplies, or that new laptop.

The final calculation is simple: 1A (GST collected) minus 1B (GST paid). If you get a positive number, you owe that amount to the ATO. If it's negative, congratulations—the ATO owes you a refund.

At its core, the BAS is a balancing act. It ensures you only pay the net difference between the GST you collected for the government and the GST you paid as a business expense.

Understanding Your Payroll and Income Tax Obligations

If you have staff or you pay your own income tax in advance through PAYG instalments, your activity statement will cover these areas too.

• W1 Total Salary, Wages, and Other Payments: If you have employees, you report the total gross amount you paid them right here. If you use Single Touch Payroll, W1 and W2 are pre-filled from your STP reports.
• W2 Amount Withheld from Payments at W1: This is the income tax (PAYG Withholding) you've held back from your employees' pay. You're now passing this on to the ATO on their behalf.
• W5 Total Amounts Withheld: W2 plus any tax withheld because a supplier didn't quote an ABN (W4) and other amounts withheld (W3). The W5 total is copied to label 4 in the summary section.

If you're in the PAYG instalments system, that section is just as important. This is how you pre-pay your own income tax throughout the year to avoid a large bill at tax time. You either pay the instalment amount the ATO works out for you (shown at T7), or you multiply your instalment income for the period (T1) by the instalment rate the ATO gives you (T2). If you expect your tax for the year to be lower, you can vary your instalment (for example, by entering your estimated tax at T8, the varied amount at T9 and a reason code at T4). The instalment you pay is carried to label 5A. Employers paying FBT instalments report them at F1 (or a varied amount at F3), carried to label 6A.

Who Needs to Lodge an Activity Statement and When

Figuring out if you need to lodge an activity statement can feel confusing, but the rules are actually quite clear once you know what to look for. Not every business owner has to do it, and understanding where you stand is the first step to avoiding missed deadlines and unnecessary stress.

The main trigger for lodging a Business Activity Statement (BAS) comes down to one thing: GST registration. If your business has a current or projected annual turnover of $75,000 or more, the law says you must register for GST. Once you're registered, lodging a BAS becomes a non-negotiable part of your tax life. This threshold ensures smaller operators and side-hustles aren’t tangled up in the same reporting as larger companies. For non-profit organisations, that bar is set higher at $150,000.

At its core, the requirement to lodge is all about accountability. If you're collecting GST on behalf of the government or withholding tax from employee wages, the ATO needs a formal way for you to report and hand over those funds. The activity statement is that official channel.

But it’s not just about GST. If your business has employees, you have to withhold tax from their wages under the Pay As You Go (PAYG) withholding system. This obligation means you must report those amounts to the ATO through an activity statement, even if you’re not registered for GST.

Your Lodgement Frequency

How often you need to report to the ATO depends on the size and turnover of your business. Your lodgement frequency is automatically set when you register for an Australian Business Number (ABN) and GST.

• Quarterly: This is the default for most small to medium-sized businesses. If your GST turnover is less than $20 million, you’ll generally lodge every three months. It's the most common cycle we see with our clients.
• Monthly: GST reporting is monthly once your GST turnover reaches $20 million, and the ATO can move businesses with a poor lodgement or payment history to monthly reporting. Some smaller businesses choose monthly reporting to keep a tighter grip on cash flow or receive regular GST refunds sooner. Businesses that withhold more than $25,000 a year from wages (medium withholders) also report and pay PAYG withholding monthly. Monthly statements are due on the 21st of the following month.
• Annually: Businesses voluntarily registered for GST with GST turnover under $75,000 ($150,000 for not-for-profits) can choose to report and pay GST once a year. Any PAYG withholding or PAYG instalments are still reported during the year.

Don't Forget the Instalment Activity Statement (IAS)

So, what happens if you have tax obligations but you're not registered for GST? This is where the Instalment Activity Statement (IAS) comes into play. You’ll lodge an IAS if you aren't registered for GST but withhold tax from employees' wages, pay PAYG instalments or (for some employers) pay FBT instalments.

On top of that, individuals and sole traders who earn significant business or investment income might be asked by the ATO to pay PAYG instalments. This is a system designed to help you pre-pay your income tax in smaller chunks throughout the year, so you don't get hit with a massive tax bill when you lodge your annual return. If this applies to you, the ATO will send you an IAS to report and pay these amounts.

Navigating Lodgement Deadlines and Avoiding Penalties

Getting your activity statements lodged on time isn’t just good housekeeping—it's absolutely critical for avoiding some hefty penalties from the Australian Taxation Office (ATO). The first step to staying in control of your business finances and keeping the ATO happy is knowing exactly when your lodgements are due.

For most small and medium businesses, this means lodging on a quarterly basis. Getting ahead of these dates is non-negotiable, as the ATO has a very strict compliance framework.

Quarterly Activity Statement Due Dates for 2026–27

Here are the standard ATO lodgement and payment due dates for quarterly activity statements in the 2026–27 financial year, along with the later dates available when a registered tax or BAS agent lodges electronically for you:

• Quarter 1 (1 July – 30 September 2026): due 28 October 2026, or 25 November 2026 if an agent lodges electronically
• Quarter 2 (1 October – 31 December 2026): due 28 February 2027 (no agent extension)
• Quarter 3 (1 January – 31 March 2027): due 28 April 2027, or 26 May 2027 if an agent lodges electronically
• Quarter 4 (1 April – 30 June 2027): due 28 July 2027, or 25 August 2027 if an agent lodges electronically (subject to ATO confirmation)

If a due date falls on a weekend or public holiday, you can lodge and pay on the next business day. Monthly activity statements are due on the 21st of the following month. It's vital to remember that these aren't just suggestions. Missing these dates triggers a cascade of financial consequences that can turn a simple oversight into a significant debt.

The Real Cost of Being Late

The ATO doesn’t mess around with late lodgements. The failure to lodge penalty is one penalty unit ($364 from 1 July 2026) for every 28 days (or part of 28 days) your statement is overdue, up to five units ($1,820) per statement for a small business. Medium businesses pay double that and large businesses five times as much.

But that’s not all. The ATO also applies the General Interest Charge (GIC) to any tax you pay late (11.51% a year for October–December 2026). It compounds daily and hasn't been tax-deductible since 1 July 2025, so a small debt can snowball quickly.

The combination of a Failure to Lodge (FTL) penalty and compounding daily interest creates a double-hit that can seriously impact your business's cash flow. What might start as a small unpaid GST amount can spiral into a debt several times larger if left unaddressed.

The Advantage of Using a Tax Professional

Here’s a crucial tip: one of the biggest advantages of working with a registered tax professional like us at Australia Wide Tax Solutions is gaining access to extended lodgement deadlines. Because we lodge electronically for our clients, the ATO gives us special agent-only due dates.

For 2026–27, quarterly statements lodged electronically through an agent are due 25 November 2026 (quarter 1), 26 May 2027 (quarter 3) and 25 August 2027 (quarter 4, subject to ATO confirmation) – up to four extra weeks. Quarter 2 stays at 28 February 2027.

That extra breathing room is invaluable. It dramatically reduces compliance stress, gives you more time to get your records in order, and is one of the best ways to avoid the penalties that come with being late. If you're already behind, our guide to late BAS lodgement and payments explains your options.

Your Step-by-Step Guide to Lodging Your Activity Statement

Lodging your Activity Statement shouldn't be a quarterly headache. When you have a solid process, it becomes just another part of your business rhythm. This guide breaks it all down into simple, repeatable steps, turning what feels like a complicated chore into a straightforward task.

Step 1: Get Your Records in Order

Before you even touch the form, you need clean and accurate records. Good bookkeeping isn't just a "nice-to-have"; it’s the absolute foundation of a painless BAS lodgement.

Start by pulling together all the key documents for the reporting period. Here’s your must-have checklist:

• Sales Records: A complete summary of your business sales, making sure to separate taxable sales from any GST-free ones.
• Expense Records: Every single receipt and invoice for business purchases where you paid GST. Don't miss any – these are your credits!
• Bank Statements: All your business bank and credit card statements. Use these to double-check your transactions so nothing slips through the cracks.
• Payroll Summary: If you have staff, you'll need the total gross wages you paid (W1) and the total tax you withheld from their pay (W2).

Having this information organised and ready to go makes everything that follows a thousand times easier. For a deeper dive, our guide on how to prepare a business activity statement is an invaluable resource.

Step 2: Choose How You'll Lodge

With your numbers sorted, it's time to decide how you're going to file your statement. You have a few options, and the right one depends on your business and your confidence level.

Choosing your lodgement method comes down to a trade-off between convenience, cost, and how comfortable you are with the process. What’s perfect for a sole trader might not work for a growing business with a team.

Here are the main ways to lodge:

• SBR-enabled accounting software (such as Xero or MYOB): highly automated and lodges straight from your bookkeeping, which cuts manual errors, but you'll need a paid subscription and some setup time.
• ATO Online services: free. Sole traders can lodge through Online services for individuals and sole traders (via myGov), and other businesses through Online services for business (signing in with myID). It's a manual process, so it's easier to make mistakes.
• A registered tax or BAS agent: they prepare and lodge for you, give you expert advice and can access later due dates, but there's a professional fee.
• Phone (nil statements only): if you have nothing to report, you can lodge a nil activity statement through the ATO's automated phone service on 13 72 26, using your TFN or ABN and the statement's document ID.
• Paper: if the ATO mails you a paper activity statement, you can complete it and post it back in the envelope provided.

Many business owners find online lodgement a good middle ground. If you're going it alone, the ATO's online services show your pre-filled labels (including W1 and W2 from your Single Touch Payroll reports), so check them against your own records before you lodge.

Step 3: Settle the Account

Once you've lodged, the final piece of the puzzle is settling up with the ATO. If the GST you collected on sales (1A) is more than the GST you paid on purchases (1B), you'll have a bill to pay.

The ATO offers plenty of ways to pay, including BPAY, credit/debit card, or setting up a direct debit.

On the flip side, if you're owed a refund, the ATO pays it into your nominated bank account once your statement is processed. A refund can be held while the ATO checks your details, and it won't be released until all your outstanding activity statements are lodged. This final step closes the loop on your Activity Statement for the period, keeping you compliant and on track.

Take Control of Your Business Tax Obligations

Getting your head around what an activity statement is is a great first step. But real control comes from getting the lodgement right, every single time.

For most business owners we talk to, managing BAS or IAS lodgements feels like a constant battle. It’s a grind of time-consuming admin, the ever-present risk of costly mistakes, and the stress of a deadline that’s always just around the corner. This is where getting the right professional support can turn a major headache into a smooth, strategic part of your business.

At Australia Wide Tax Solutions, our BAS lodgement service is designed to take this pressure off your shoulders. Our accountants check every detail, make sure every credit you're entitled to is claimed, and lodge your statements on time.

The Benefits of Expert Support

Working with us is about more than just ticking a compliance box; it’s about giving you genuine peace of mind. Here’s what our clients gain:

• Extended Lodgement Deadlines: As registered tax agents, we get access to later due dates from the ATO, giving you valuable breathing room to get your information together.
• Maximised Credits: We comb through your expenses to ensure you claim every dollar of GST credit you're entitled to. This directly improves your cash flow.
• Careful Review: Our professional review process catches the small errors that can attract unwanted ATO attention and penalties.

We provide expert guidance tailored for small businesses and property investors, all backed by convenient online services. When our team is handling your activity statements, you can get back to focusing your energy on what you actually love doing—running and growing your business.

Let us help you turn your tax obligations into a seamless and efficient part of your financial strategy.