Your first BAS: a calm beginner's guide for new businesses

For a lot of new business owners, the first BAS is the moment tax becomes real. Until then, the GST you’ve charged customers has been sitting quietly in your account, feeling a lot like your money. Then the BAS arrives and asks for it back.

This guide makes sure that moment is calm, not stressful. It’s written for beginners, and it’ll help you whether you do your own BAS or use a registered tax or BAS agent.

What is a BAS, in plain English?

A BAS (business activity statement) is a form you lodge with the ATO, usually every quarter, to report and pay certain taxes. For most small businesses, the main things on it are:

• GST — the goods and services tax you’ve charged customers, minus the GST you’ve paid on business purchases
• PAYG withholding — tax you’ve held back from employees’ wages, if you have staff
• PAYG instalments — prepayments towards your income tax, if the ATO has put you into the system

Think of it as the business’s regular catch-up with the ATO: “here’s what I collected on your behalf, and here’s what I owe.”

Do you need to lodge one?

You’ll need to lodge a BAS if you’re registered for GST, or if you have other obligations reported on it, like PAYG withholding for employees.

The ATO’s rules on GST registration are:

Situation	GST registration
GST turnover of $75,000 or more	Required; register within 21 days of reaching it
Non-profit, GST turnover of $150,000 or more	Required
Taxi or ride-sourcing services	Required, whatever the turnover
GST turnover under $75,000	Optional

Source: ATO, Registering for GST (updated September 2026).

If you’re under the threshold, you can still choose to register. Some owners do, for example if most of their customers are businesses that can claim the GST back. Your accountant can help you decide. Our lesson on ABN and GST explains why lenders check this too.

When is your BAS due?

Most small businesses lodge quarterly. The ATO’s due dates are:

Quarter	Period covered	Due date
Q1	July – September	28 October
Q2	October – December	28 February
Q3	January – March	28 April
Q4	April – June	28 July

Source: ATO, Due dates for lodging and paying your BAS (updated September 2026).

A few extra points from the ATO:

• Businesses with GST turnover of $20 million or more lodge monthly, due on the 21st of the following month.
• If you lodge online, you may get an extra two weeks for quarterly BAS. Registered agents may also have extended arrangements.
• That extra time doesn’t apply to Q2, because its due date already includes a longer period.

Put all four dates in your calendar now, with a reminder two weeks before each.

What goes on the BAS?

Here’s the gentle version of the main GST lines:

• Total sales for the quarter, including GST.
• GST on sales — the GST included in what you charged customers. For a GST-inclusive price, the GST is one-eleventh of the total.
• GST on purchases — the GST included in eligible business purchases, which you can claim back as a credit.
• The difference is what you pay (or, if you paid more GST than you collected, what the ATO refunds).

Illustrative example. A new mobile massage business registered for GST collects $33,000 in sales for the quarter, including $3,000 of GST. It spent $5,500 on business purchases that included $500 of GST. Its GST for the quarter is roughly $3,000 − $500 = $2,500. (Illustrative and simplified; your BAS may include other items.)

If you have staff, PAYG withholding appears too. And remember that from 1 July 2026, under Payday Super, the ATO says super must reach employees’ funds within 7 business days of payday. Super isn’t paid through your BAS, but it’s another regular outgoing that now sits alongside wages.

How do you avoid the first-BAS shock?

The shock comes from spending GST as if it were income. The fix is simple, and it’s the single best money habit a new business can build:

Move tax money aside every week.

1. Open a separate “tax” account (a savings account at your bank is fine).
2. Each week, transfer the GST portion of your sales into it. For GST-inclusive sales, one-eleventh is a good starting estimate.
3. If you have staff, move PAYG withholding there too.
4. Add a little extra towards income tax.
5. Don’t touch it until the BAS is due.

When the BAS arrives, the money’s already waiting. It also makes your cash flow forecast much easier to manage.

What if you can’t pay it all?

It happens, especially in the first year. The most important rule: lodge on time anyway.

Lodging shows you’re engaged and keeps penalties for late lodgement away. Then contact the ATO about paying. The ATO offers payment plans, and it notes that debts on a payment plan continue to accrue general interest charge (GIC), which compounds daily, so paying sooner costs less.

Lenders see this too. A business with an ATO debt that’s lodging on time and keeping to a payment plan is viewed very differently from one that’s gone quiet. ATO debt is considered case by case. Our lesson on bad credit or ATO debt explains how lenders look at it.

If a BAS bill has landed at an awkward time and you’d like to understand your options, you can start a no-credit-check enquiry and a real person will talk it through with you.

Should you do your own BAS or use an agent?

Both are fine. It depends on your confidence and your time.

Doing it yourself can suit simple businesses with good bookkeeping software. The ATO’s online services let you lodge directly.

Using a registered tax or BAS agent can suit you if:

• you have staff, several income streams or unusual purchases
• you’d rather spend your time running the business
• you want someone to check your GST claims are right

Whichever you choose, keep your records organised. Lenders often ask for recent BAS, and the sales on it should match the story in your bank statements. Documents, explained shows where the BAS fits.

A first-BAS checklist

• GST registration confirmed (check your ABN on ABN Lookup)
• Quarterly due dates in your calendar, with reminders
• Separate tax account opened
• Weekly transfer set up for the GST portion of sales
• Bookkeeping up to date, with receipts for purchases
• Decided: do it yourself, or use an agent
• Plan for what you’ll do if the amount is more than expected

How does this connect to borrowing?

Good BAS habits are also good borrowing habits. Lodging on time, keeping tax aside and matching your reported sales to your bank statements all make you a clearer, stronger applicant when the day comes that you want a loan for growth. They’re also three of the areas our loan-readiness quiz checks.

Myths about the first BAS

“GST is my money until the BAS is due.” It’s money you’ve collected on the ATO’s behalf. Treat it as borrowed from the start and you’ll never be caught short.

“If I can’t pay, I shouldn’t lodge.” The opposite. Lodging on time and then arranging payment is far better than going quiet.

“A refund means I did something wrong.” Not necessarily. In a quarter with big purchases, such as new equipment, the GST you paid can be more than the GST you collected, and the difference comes back to you.

“My bookkeeper handles it, so I don’t need to understand it.” Your bookkeeper or agent does the work, but it’s still your business’s tax. Knowing the basics means you can spot errors and plan cash flow around it.

Want to talk about tax time and cash flow?

Your first BAS doesn’t need to be scary. With a separate tax account, the due dates in your calendar and a plan if things get tight, it becomes just another quarterly routine.

If tax time has shown up a cash gap, or you’re planning ahead for growth, our enquiry takes about a minute. There’s no credit check to ask, and we don’t spray your details across multiple lenders. A real person talks through your situation, including any ATO balance, in plain English. Please be accurate about your tax position on the form so we can suggest options that genuinely fit.

Talk to a real person about your options →