Preparing a Business Activity Statement can feel like a big job, especially when receipts, payroll reports and GST codes are scattered across the business. I have seen many owners leave BAS until the final week, then spend nights chasing missing invoices. A better system saves stress.
This guide walks through the BAS process from records to submission, using plain English, practical checks and examples that suit Australian small businesses dealing with ATO reporting each quarter, month or year.
Why Your BAS Starts Long Before Lodgement Day
A BAS is not something you prepare only when the due date appears on the calendar. The real work starts each time you issue an invoice, pay a supplier, run payroll or reconcile your bank account.
In our bookkeeping work with small business owners, most BAS problems do not begin with the ATO form. They begin with missing receipts, wrong GST codes, unreconciled bank feeds or payroll figures that do not match Single Touch Payroll reports. By the time the BAS is due, those small gaps can turn into a dog’s breakfast.
A clean BAS starts with clean records. That means every sale, expense, wage payment and GST amount needs to be recorded in the right place. If your business uses Xero, MYOB or QuickBooks, the software can do a lot of the heavy lifting. Still, the software only works well when the setup is correct and the information going in is accurate.
What A BAS Reports To The ATO
A Business Activity Statement reports tax amounts your business has collected, paid or needs to pay. The most common BAS items for small businesses include:
- GST collected on sales
- GST paid on business purchases
- PAYG withholding from employee wages
- PAYG income tax instalments
- Fuel tax credits, if relevant
- Other taxes such as FBT instalments, Wine Equalisation Tax or Luxury Car Tax, where they apply
For many Australian small businesses, GST and PAYG withholding are the main focus. GST is the 10% tax added to most taxable sales. PAYG withholding is the tax taken from employee wages and sent to the ATO.
The BAS brings these figures together so the ATO can see what your business owes or what credit may apply.
Who Needs To Lodge A BAS In Australia
Your business generally needs to lodge a BAS if it is registered for GST. You must register for GST if your annual turnover is $75,000 or more. Non-profit organisations have a higher threshold of $150,000.
Taxi and rideshare drivers need to register for GST regardless of turnover. That includes Uber and similar services.
Some smaller businesses choose to register for GST before they reach the threshold. This can make sense in certain cases, especially if they work with larger clients or want to claim GST credits on business purchases. Still, voluntary registration also means regular BAS lodgement, so it should not be done on a whim.
Why BAS Accuracy Matters For Cash Flow
BAS is not just a compliance task. It affects cash flow.
A strong sales quarter can look exciting on paper, but part of that money may belong to the ATO. If a business spends all the GST it collected, the BAS bill can bite hard later.
Here is a simple example:
| Sale Amount | GST Included | Amount That Is Not Yours To Keep |
| $1,100 | $100 | $100 |
| $5,500 | $500 | $500 |
| $11,000 | $1,000 | $1,000 |
A Melbourne tradie might invoice $33,000 in a busy quarter. If those invoices include GST, $3,000 may need to be reported as GST collected before expense credits are applied. That is why many business owners keep a separate savings account for GST and tax. It is not fancy, but it works.
The Records You Need Before You Prepare A Business Activity Statement
A good BAS starts with proof. The ATO does not want rough guesses, and neither should you. If a number appears on your BAS, your records should explain where it came from.
This is where many business owners get caught. They know they paid for fuel, stock, software, materials or subcontractors, but the receipt is missing. Or the invoice is in someone’s inbox. Or the bank feed shows a payment to “ABC Pty Ltd”, but nobody remembers what the purchase was for. That is when BAS preparation slows down.
The fix is simple, but it needs routine. Keep records as you go. Do not wait for BAS week.
Your BAS Record Checklist
Before you prepare a BAS, gather the records that support your sales, purchases, GST and payroll figures.
Use this checklist:
- Sales invoices and receipts
- Supplier tax invoices
- Bank and credit card statements
- Payroll reports
- PAYG withholding records
- Superannuation records
- Fuel tax credit records, if your business claims them
- Loan or finance documents, where relevant
- Notes for private-use adjustments
- Previous BAS reports
- ATO correspondence
- Accounting software reports from Xero, MYOB or QuickBooks
A small retail shop, for example, may need daily takings reports, EFTPOS settlements, supplier invoices, stock purchase records and payroll summaries. A builder may need subcontractor invoices, materials receipts, vehicle expense records and job income reports.
Different businesses need different records. The rule of thumb is this: if it affects GST, wages, PAYG or business income, keep it.
How Long You Need To Keep BAS Records
Australian businesses generally need to keep tax and business records for at least five years. Some records may need to be kept longer, depending on the type of transaction or business situation.
Cloud accounting makes this much easier. Instead of keeping shoeboxes full of faded receipts, you can attach invoices and receipts directly to transactions in Xero, MYOB or QuickBooks. That way, if you need to check a BAS figure later, you can find the document without turning the office upside down.
I have seen business owners spend hours searching for a $200 invoice during BAS review. The amount was small, but the time lost was not. Good filing saves more than paper. It saves your patience.
Cash Versus Accrual BAS Reporting
Your BAS reporting method affects when you report GST.
Some businesses report on a cash basis. Others report on an accrual basis. The difference matters because it changes which sales and purchases appear in each BAS period.
| BAS Reporting Method | GST Is Reported When | Commonly Suits |
| Cash basis | Money is received from customers or paid to suppliers | Smaller businesses that watch cash flow closely |
| Accrual basis | Invoices are issued or received, even if unpaid | Larger or more complex businesses with higher transaction volume |
Under the cash method, you report GST when payment happens. If a customer pays your invoice in October, the GST appears in the BAS period that includes October.
Under the accrual method, you report GST when the invoice is issued or received. If you send an invoice in September but get paid in October, the GST may still belong in the September quarter.
This is why you should know your reporting basis before preparing your BAS. Mixing the two can create errors that carry from one quarter to the next.
How To Prepare Business Activity Statement Figures Step By Step
Once your records are in order, you can start preparing the figures. This is where the keyword becomes the practical question: how to prepare business activity statement figures without missing important BAS labels?
The answer is to follow a clear order. Reconcile first. Review GST second. Check payroll third. Then look for odd amounts before you lodge.
Step 1: Reconcile Your Bank Accounts
Bank reconciliation means matching the money in your bank account with the transactions in your accounting records.
Every deposit should match a sale, transfer, refund or other income item. Every withdrawal should match a bill, wage payment, loan payment, tax payment or business expense.
Do not skip this step. If the bank is not reconciled, the BAS report may be wrong.
A simple monthly routine helps:
- Import bank transactions into your accounting software.
- Match each transaction to the correct invoice, bill or account code.
- Check that GST has been coded correctly.
- Investigate anything unusual.
- Reconcile all business bank accounts and credit cards.
For a busy hospitality business, this may include EFTPOS settlements, delivery platform income, supplier payments, wages, superannuation and cash deposits. One missed merchant fee or duplicated sale can throw the figures out.
Step 2: Check Sales And GST Collected
The BAS label G1 reports total sales. This includes taxable sales, GST-free sales and some other income items, depending on your business activity.
The BAS label 1A reports GST on sales. This is the GST your business collected from customers.
If a taxable sale is GST-inclusive, divide the total by 11 to find the GST amount.
| GST-Inclusive Sale | GST Amount |
| $110 | $10 |
| $1,100 | $100 |
| $11,000 | $1,000 |
For example, if a Melbourne mechanic invoices a customer $1,100 for taxable services, the GST collected is $100. The remaining $1,000 is business income before expenses.
Be careful with GST-free sales. Some food, medical services and exports may not include GST. These still need correct coding, but they should not be treated the same as taxable sales.
Step 3: Check Purchases And GST Credits
The BAS label 1B reports GST credits on business purchases. These are also called input tax credits.
You can usually claim GST credits when:
- The purchase was for your business.
- The supplier charged GST.
- The supplier is registered for GST.
- You hold a valid tax invoice for purchases over $82.50.
- The purchase is not private or blocked from GST claims.
A common mistake is claiming GST on every expense. Some expenses do not include GST. Bank fees, wages, some government charges and certain insurance items may have different GST treatment.
Another trap is overseas software. A monthly subscription may or may not include Australian GST. Do not assume. Check the invoice.
A practical habit is to scan large expenses before BAS lodgement. If a $4,400 equipment purchase appears in the quarter, check the invoice. If GST was included, the GST credit may be $400. If no GST was charged, claiming $400 would be wrong.
Step 4: Review Wages And PAYG Withholding
If your business has employees, payroll figures need close attention before you lodge your BAS.
The BAS label W1 reports total gross wages and other payments subject to PAYG withholding. The BAS label W2 reports the tax withheld from those payments.
This is where payroll reports, pay runs and Single Touch Payroll records should line up. If they do not match, stop and check the reason before you lodge. A small payroll error can snowball across the year.
For example, a plumbing business in Melbourne may have three employees, one apprentice and one casual admin worker. If the owner runs payroll each week but forgets to finalise one pay run in the software, the BAS may under-report PAYG withholding. That can create stress later when the ATO records do not match the business records.
Before lodging, check:
- Gross wages for the BAS period
- PAYG withholding for the BAS period
- Any allowances, bonuses or termination payments
- STP reports
- Superannuation records
A BAS is not the place for guesswork. Payroll touches employees, tax and super, so it deserves a clean review.
Step 5: Check PAYG Instalments
PAYG instalments help businesses prepay income tax during the year. The ATO often calculates the instalment amount based on past income tax details.
On a BAS, this may appear at label T7. For many businesses, the amount is pre-filled.
Do not change a pre-filled PAYG instalment without understanding the reason. If your business income has changed, you may be able to vary the amount, but this needs care. Varying too low can lead to an interest or a catch-up tax bill later.
A simple way to think about PAYG instalments is this: GST relates to transactions. PAYG instalments relate to business income tax. They are not the same thing, even though they may appear on the same BAS.
Step 6: Check Private Expenses And Mixed-Use Purchases
Business owners often pay for mixed-use items. Phones, internet, vehicles and home office costs are common examples.
If an expense is partly private, you should only claim the business-use portion.
Here is a simple example:
| Expense | Total Cost | Business Use | BAS Claim Approach |
| Mobile phone bill | $110 | 70% | Claim 70% of the business expense and GST credit |
| Internet bill | $88 | 50% | Claim 50% of the business expense and GST credit |
| Vehicle running cost | $220 | 80% | Claim 80% if supported by records |
A sole trader who uses one mobile phone for both client calls and family use should not claim the full GST credit unless the phone is 100% business use. Keep it fair, keep it supported, and keep the books clean.
Common BAS Mistakes That Cost Small Businesses Time And Money
Most BAS mistakes are not dramatic. They are usually small errors repeated over time.
One wrong GST code may not seem like much. But if it appears across hundreds of transactions, the final BAS figure can be well off the mark. That is why regular review matters.
Claiming GST Without A Valid Tax Invoice
For purchases over $82.50, you generally need a valid tax invoice to claim a GST credit. A bank transaction alone is not always enough.
“No invoice, no GST credit. That small rule can save a lot of backtracking later.”
A card statement may prove that money left the account, but it may not show whether GST was charged. The tax invoice gives the detail.
Treating GST-Free Sales As Taxable Sales
Some sales are GST-free. Examples can include basic food, certain medical services and some exports.
If a business treats GST-free sales as taxable, it may overstate GST collected. If it treats taxable sales as GST-free, it may underpay GST. Neither is ideal.
A mixed food business is a good example. A café may sell taxable hot meals and GST-free basic food items. If all sales are coded the same way, the BAS may not reflect the real GST position.
Double-Counting Purchases Or Sales
Double-counting happens when the same transaction enters the accounts twice. It may happen when a receipt is uploaded manually and the bank feed also imports the payment.
It can also happen when supplier bills are entered twice by mistake.
This is an easy trap. I have seen a business claim the same equipment purchase twice because one copy came from an email invoice and the other came through a bank rule. The owner did not mean to do anything wrong. The system was just messy.
Including Personal Costs In Business BAS Claims
Personal expenses do not belong in BAS claims.
Common examples include:
- Family meals
- Personal groceries
- Mortgage payments
- School costs
- Personal travel
- Clothing that is not a required uniform or protective workwear
If you accidentally pay a private cost from the business account, code it correctly. Do not claim GST just because the payment came from the business bank card.
Lodging Late, Even When The BAS Is Nil
A Nil BAS still needs to be lodged if the ATO expects one.
If your business had no sales and no purchases for the period, you may think there is nothing to do. The ATO may think differently. If a BAS is issued, lodge it by the due date.
Late lodgement can lead to penalties and interest. It can also affect your relationship with the ATO if the pattern continues.
BAS Lodgement Options: Choose The Right Path For Your Business
Once the figures are reviewed, the next step is lodgement. The right option depends on your business size, software, confidence and available time.
Some owners can lodge their own BAS with no trouble. Others are better off using a registered BAS agent, especially if payroll, GST adjustments, inventory or prior errors are involved.
Lodge Through ATO Online Services
Many businesses lodge through ATO online services using myID. Sole traders may also use myGov for some tax tasks.
This option can suit a business with simple records and confidence in its BAS figures. The key point is to prepare the numbers before logging in. Do not use the ATO form as your working paper.
Lodge Through Xero, MYOB Or QuickBooks
Cloud accounting software can make BAS lodgement easier. Xero, MYOB and QuickBooks can help prepare reports, calculate GST and store supporting records.
The catch is setup. Software will not fix poor coding by itself. If the GST settings are wrong, the BAS report may also be wrong.
For example, a retail business with stock, freight, merchant fees and online sales needs clear GST rules. If everything is coded to one default account, the BAS may miss key details. The software is useful, but it is not a magic wand.
Lodge Through A Registered BAS Agent
A registered BAS agent can prepare, review and lodge BAS on behalf of your business.
This can be a wise move if your business has:
- Employees
- Contractors
- Complex GST treatment
- Inventory
- Multiple locations
- ATO payment plans
- Prior BAS errors
- Fast growth
- Limited bookkeeping time
In our experience, many business owners ask for help after a BAS problem has already become urgent. It is much easier to fix the process earlier. A stitch in time saves nine.
Lodge A Nil BAS
A Nil BAS applies when your business has nothing to report for the period. This may happen if the business did not trade, did not make purchases and had no GST or PAYG amounts to report.
Still, if the ATO has issued a BAS, you need to lodge it. You can usually lodge a Nil BAS online, through your registered agent, or by using the ATO’s automated phone service where available.
Do not ignore it because the amount is zero. Nil does not mean optional.
BAS Due Dates Australian Businesses Need To Know
BAS due dates depend on your reporting cycle. Some businesses lodge monthly. Many small businesses lodge quarterly. Some eligible businesses lodge annually.
Mark the dates in your calendar before the year gets busy. A reminder one week before the due date is helpful, but a reminder three weeks before is better. That gives you time to chase missing invoices, reconcile accounts and check payroll.
Monthly BAS Due Dates
Monthly BAS lodgement is usually due on the 21st day of the following month.
For example, a March monthly BAS is generally due on 21 April. This cycle is common for larger businesses, but some smaller businesses also choose monthly reporting to keep GST payments smaller and more regular.
Quarterly BAS Due Dates
Most small businesses that lodge quarterly follow this schedule:
| BAS Quarter | Period Covered | Standard Due Date |
| Quarter 1 | July to September | 28 October |
| Quarter 2 | October to December | 28 February |
| Quarter 3 | January to March | 28 April |
| Quarter 4 | April to June | 28 July |
If you lodge through a registered BAS or tax agent, you may receive extra time, depending on your circumstances. Check before assuming.
Annual BAS Due Date
Annual GST reporting is generally due by 31 October, where the business is eligible for annual reporting.
This may suit very small businesses with simple GST needs, but it is not right for everyone. Waiting a full year can make GST harder to track if the books are not kept up to date.
How Cloud Accounting Makes BAS Preparation Easier
Cloud accounting can turn BAS from a scramble into a routine. It helps you store records, match transactions and review GST before lodgement.
What BAS Software Can Automate
Good software setup can help with:
- Bank feeds
- GST coding
- Invoice matching
- Payroll reports
- BAS summaries
- Digital record storage
- Direct lodgement support
The key is review. Automation helps, but someone still needs to check the result.
Why Setup Matters More Than The Software Brand
Xero, MYOB and QuickBooks can all support BAS preparation. The real question is whether the file has been set up for your business.
A manufacturer, for example, may need inventory, job costing and supplier tracking. A local café may need daily takings, payroll and merchant fee coding. Different businesses need different systems.
Final BAS Review Before You Submit
Before you lodge, pause and check the BAS as a whole.
The 10-Minute BAS Sense Check
- Are all bank accounts reconciled?
- Do sales match your reports?
- Does GST collected look reasonable?
- Are large purchases supported by tax invoices?
- Have private costs been removed?
- Do payroll reports match W1 and W2?
- Are ATO pre-filled amounts correct?
- Is the BAS period right?
- Can the business pay by the due date?
- Have old errors been reviewed?
BAS Preparation Is Easier With A Clear System
BAS preparation becomes easier when records stay current, GST codes are correct and payroll is checked before lodgement day. The process is not about rushing through an ATO form. It is about keeping reliable records so each BAS tells the right story.
For small business owners, the best habit is simple: reconcile often, keep invoices, review GST and ask for help before the wheels fall off.
