What is a BAS Statement in Australia? Due Dates, Lodgement & How a BAS Agent Helps

If you’re GST-registered and the words “BAS due date” make your stomach drop a little, you’re not alone. Every quarter (or month), thousands of Perth business owners scramble to pull together their sales, expenses, and payroll figures before the Australian Taxation Office (ATO) deadline hits. A Business Activity Statement, or BAS statement, is one of the most important – and most misunderstood – compliance obligations for small businesses in Australia. This guide breaks down exactly what a BAS is, who needs to lodge one, the key 2026-27 due dates, and how working with a registered BAS agent can take the stress (and the guesswork) out of the process.

What is a BAS Statement?

A BAS statement is a form you lodge with the ATO to report and pay several business tax obligations in one go. Think of it as a regular check-in with the tax office where you tally up what you’ve collected on their behalf (like GST) and what you owe or are owed back.

Most businesses that are registered for GST need to lodge a BAS. This generally includes:

• Sole traders, partnerships, companies and trusts with a GST turnover of $75,000 or more (or $150,000 for non-profits)
• Ride-sharing and taxi drivers, regardless of turnover
• Any business that has voluntarily registered for GST

If your business isn’t GST-registered, you won’t need to lodge a full BAS – though you may still have other ATO reporting obligations, such as an Instalment Activity Statement (IAS) if you have PAYG withholding but no GST registration.

What Goes Into a BAS?

A BAS isn’t just about GST. Depending on your business setup, it can capture several different obligations in a single statement:

1. Goods and Services Tax (GST): You report GST collected on sales (GST on your income) and GST paid on business purchases (GST credits). The difference is either paid to the ATO or refunded to you.
2. PAYG Withholding: If you employ staff, you withhold tax from their wages and report this amount on your BAS, alongside the total wages paid for the period.
3. PAYG Instalments: This is a prepayment towards your expected annual income tax bill, calculated either as a percentage of income or a fixed instalment amount set by the ATO.

Some businesses will also report luxury car tax, wine equalisation tax or fuel tax credits on their BAS, depending on their industry. Getting each of these categories right – and coded correctly in your accounting software – is where many business owners start to feel out of their depth, particularly if bookkeeping isn’t done consistently throughout the quarter.

BAS Due Dates 2026-27

Most small businesses lodge quarterly, but larger businesses (GST turnover of $20 million or more) must lodge monthly. Here’s how the 2026-27 dates stack up.

Quarterly BAS Due Dates 2026-27

The Q2 due date already includes a built-in extension over the Christmas period, so no further concession applies. Note it falls on a Sunday in 2027, pushing the effective deadline to Monday 1 March 2027.

Monthly BAS Due Dates

Monthly lodgers report and pay by the 21st day of the following month. A registered agent concession only applies to the December monthly BAS, extending the deadline to 21 February 2027.

If any due date falls on a weekend or public holiday, the ATO automatically shifts it to the next business day.

Missing these deadlines isn’t just a paperwork issue – it comes at a real cost. From 1 July 2026, the failure-to-lodge penalty rose to $364 for every 28 days your BAS remains outstanding (up to a maximum of five penalty units), plus a general interest charge currently sitting at 11.43% per annum, which is no longer tax-deductible.

How to Lodge BAS

There are three main ways to lodge a BAS in Australia:

1. Through ATO Online Services – You can lodge directly via your myGov account (for sole traders) or the ATO’s Online Services for Business portal. This works fine if your records are simple and up to date.
2. Through Accounting Software – Platforms like Xero and MYOB allow you to prepare and lodge your BAS directly from your accounting file, using pre-filled GST and PAYG figures pulled straight from your transactions. This significantly reduces manual entry errors compared to lodging from scratch.
3. Through a Registered BAS Agent – A registered BAS agent lodges on your behalf as part of the ATO’s official Lodgment Program. This is where the concession dates above really pay off – agent-lodged BAS statements generally receive an extra two to four weeks compared to the standard deadline, giving you valuable breathing room to review figures and plan for any payment due.

Common BAS Mistakes to Avoid

Even diligent business owners trip up on BAS reporting. Some of the most frequent errors we see include:

• Incorrect GST coding – claiming GST credits on GST-free items (like basic food or bank fees) or missing credits on legitimate business expenses
• Reconciliation gaps – lodging before bank accounts and credit cards are fully reconciled, leading to under- or over-reported figures
• Mixing up cash vs accruals reporting – using the wrong basis for how your business is registered
• Missing PAYG withholding on contractor payments where withholding actually applies
• Leaving it to the last minute – rushing figures the night before the deadline, increasing the risk of errors

For a broader look at where small businesses commonly go wrong with their books, our earlier post on common bookkeeping mistakes and how to avoid them covers several of these issues in more depth.

Why Hire a Registered BAS Agent

Lodging your own BAS is entirely legal, but many Perth business owners find that a registered BAS agent pays for itself many times over. Here’s why:

• Extra lodgement time: agent-lodged BAS statements come with concession dates, giving you weeks of extra breathing room
• Accuracy: a qualified agent knows exactly how GST, PAYG withholding and PAYG instalments should be coded and reported, reducing the risk of ATO review or penalty
• Legal protection: because BAS agents are registered with the Tax Practitioners Board, you have a safe harbour from certain penalties if the agent has taken reasonable care
• Cash flow clarity: your bookkeeper can flag your expected BAS liability well ahead of time, rather than surprising you on lodgement day

This is exactly where Bookkeeping Perth WA comes in. Our team of registered BAS agents in Perth handles everything from ongoing reconciliation to full BAS preparation and lodgement, so you’re never guessing what you owe or scrambling before a deadline. We also work closely with clients on cash flow management, forecasting upcoming BAS and tax obligations so payments never catch your business off guard.

Get Your BAS Sorted, Stress-Free

BAS lodgement doesn’t need to be a quarterly source of anxiety. With accurate, up-to-date books and the right support, it can be a routine – even predictable – part of running your business. If you’d rather hand BAS preparation and lodgement to a trusted local expert, our registered BAS agents are here to help.

Enquire now and let Bookkeeping Perth WA take BAS off your plate for good.

FAQ

Q.1 Can I lodge my BAS myself? 

Yes. If you’re comfortable with your bookkeeping and GST coding, you can lodge directly through myGov, the ATO’s Online Services for Business, or compatible software like Xero and MYOB. Just be aware that self-lodgers don’t receive the extended concession dates that registered agents do.

Q.2 What happens if I miss a BAS deadline? 

The ATO can apply a failure-to-lodge penalty, calculated in 28-day blocks, plus general interest charges on any amount owing. Repeated late lodgement can also increase ATO scrutiny of future statements. If you’re going to miss a deadline, it’s best to contact the ATO or your BAS agent proactively rather than staying silent.

Q.3 How is BAS different from a tax return? 

A BAS is typically lodged quarterly or monthly and covers GST, PAYG withholding and PAYG instalments. Your income tax return is an annual lodgement that reconciles your total income and deductions for the full financial year. They serve different purposes but work together as part of your overall ATO obligations.

Q.4 BAS agent vs accountant – what’s the difference? 

A registered BAS agent is specifically authorised to prepare and lodge BAS statements and provide GST/PAYG advice. An accountant may offer broader tax and financial advice, including income tax returns and business structuring. Many small businesses use both, or work with a bookkeeping firm that covers BAS agent services alongside day-to-day accounts.