Every quarter, millions of Australian small businesses go through the same ritual: download bank statements, open a spreadsheet, and spend hours sorting transactions into GST and non-GST buckets. There has to be a better way.
There is. You do not need to sign up for Xero ($25-$65/month). You do not need to learn MYOB. You do not need to pay an accountant $200+ to do something that is fundamentally just sorting and adding.
All you need is a bank CSV and a way to categorise the transactions. Here are the three methods, from most painful to least.
Method 1: The spreadsheet (free, slow)
Open your bank CSV in Excel or Google Sheets. Add three columns: Category, GST Status, and GST Amount.
Go through every row:
- Read the description (e.g. "BUNNINGS MAROOCHYDORE")
- Decide the category (e.g. "Materials")
- Decide the GST status (e.g. "GST-inclusive" because Bunnings charges GST)
- Calculate the GST amount (divide the amount by 11 for GST-inclusive transactions)
Repeat 200 to 500 times per quarter.
Average time to manually categorise a quarter's worth of sole trader bank transactions in a spreadsheet.
Once you have categorised everything, use SUMIF formulas to total up GST on sales (1A) and GST on purchases (1B). Subtract 1B from 1A to get your net GST (Item 5).
Pros: Free. Full control.
Cons: Brutally slow. Easy to make mistakes. You need to know which merchants charge GST and which do not. No error checking.
Method 2: Accounting software (expensive, ongoing)
Sign up for Xero ($25/month Starter, $49/month Standard) or MYOB ($25-$65/month). Connect your bank feed. Set up categorisation rules. Reconcile transactions throughout the quarter.
Pros: Bank feeds update automatically. Can handle invoicing, payroll, and more. Your accountant can log in and review.
Cons: Monthly subscription whether you use it or not. Learning curve. You need to maintain it throughout the quarter, not just at BAS time. Overkill for sole traders who just need BAS numbers.
| Software | Monthly cost | Annual cost | Good for |
|---|---|---|---|
| Xero Starter | $25 | $300 | Very small businesses, limited invoices |
| Xero Standard | $49 | $588 | Most sole traders and small businesses |
| MYOB Essentials | $25 | $300 | Sole traders who prefer MYOB |
| MYOB Business | $65 | $780 | Businesses with employees |
Method 3: AI CSV upload (fast, pay per use)
Upload your bank CSV to TaxBench. The AI reads every transaction description and automatically assigns:
- Income or expense classification
- Business category (materials, fuel, phone, rent, professional services, etc.)
- GST status (GST-inclusive, GST-free, input-taxed, out of scope)
You review the categories in a table. Fix any the AI got wrong (it typically gets 85-95% right on the first pass). Then switch to the BAS tab and your numbers are there: G1, G2, G3, 1A, G10, G11, 1B, Item 5.
Pros: 10 minutes instead of 3 hours. $29 per upload instead of $300+/year. No ongoing software to maintain. Works with any Australian bank CSV.
Cons: AI categorisation is not 100% perfect. You still need to review. Does not replace full-year accounting for complex businesses.
Which method is right for you?
| You are... | Best method | Why |
|---|---|---|
| Sole trader, simple expenses | AI CSV upload | Fastest path to BAS numbers. $29/quarter beats $300+/year for software you barely use. |
| Sole trader with employees | Xero/MYOB | You need payroll and STP reporting. Full software makes sense. |
| Company or trust | AI CSV upload + accountant review | Get your BAS numbers fast, then have your accountant review before lodging. |
| Investment portfolio | AI CSV upload | Categorise dividends, interest, capital gains. Get your EOY summary for tax return prep. |
| Business with 5+ employees, inventory | Xero/MYOB + accountant | Complex enough to justify full accounting software. |
The GST status cheat sheet
The hardest part of BAS prep is knowing which transactions include GST. Here is a quick reference for common sole trader expenses:
| Expense | GST? | Notes |
|---|---|---|
| Tools from Bunnings / Total Tools | Yes | Standard retail GST |
| Fuel from servo | Yes | GST + possible fuel tax credits |
| Office supplies (Officeworks) | Yes | Standard retail GST |
| Phone / internet bill | Yes | Telcos charge GST |
| Vehicle rego | No | Government fee, no GST |
| Insurance | Yes (mostly) | GST applies to premiums, not stamp duty |
| Bank fees | No | Financial supply, input-taxed |
| Uber / taxi | Yes | All ride-share providers charge GST |
| Rent (commercial) | Yes | If landlord is GST-registered |
| Rent (residential/home office) | No | Residential rent is input-taxed |
| Superannuation contributions | No | Not a taxable supply |
| Council rates | No | Government levy, no GST |
| Accounting fees | Yes | Accountants charge GST |
| Software subscriptions | Yes | If AU-based supplier (check invoice) |
Upload your bank CSV. Get your BAS numbers.
TaxBench categorises every transaction and calculates your GST totals automatically. Works with CBA, NAB, ANZ, Westpac, and any bank CSV.
Try TaxBench — $29 per upload →No subscription. No software to learn. Just upload and go.
Bottom line
For sole traders and simple small businesses, paying $300 to $780 a year for accounting software you only touch at BAS time is a waste. Paying an accountant $150+ per quarter for what is essentially a sorting exercise is also hard to justify.
Download your bank CSV. Upload it. Review the AI categories. Get your numbers. Lodge. Done.