If you're a sole trader tradie registered for GST, working out how to do your BAS as a sole trader is something you'll face every quarter — and it trips up a lot of people the first few times. The Business Activity Statement (BAS) is how you report GST, and sometimes PAYG instalments, to the ATO. Miss it or get the numbers wrong, and you risk penalties and interest.
The good news: once you understand the handful of labels that actually apply to a typical tradie business, lodging your BAS becomes a 20-minute job each quarter. This guide walks through exactly what's involved.
Disclaimer: TradesBill is not a registered tax agent. This guide explains the general process for informational purposes only. Always confirm your specific obligations with a registered tax agent or BAS agent, or check the ATO website directly.
What is a BAS, and do sole traders need to lodge one?
A Business Activity Statement is a form you submit to the ATO to report and pay several tax obligations in one go — most commonly GST, but also PAYG instalments and PAYG withholding if you employ staff.
As a sole trader, you need to lodge a BAS if you're registered for GST. Registration is compulsory once your annual turnover reaches $75,000, but you can also register voluntarily below that threshold. If you're not registered for GST, you generally don't need to lodge a BAS at all — you'll instead report your business income through your individual tax return at the end of the financial year.
Once you're registered, the ATO automatically sends you a BAS (or notifies you it's due) for each reporting period, and you're required to lodge it on time even if you had zero sales for the quarter.
How often do sole traders lodge a BAS?
Most sole trader tradies lodge quarterly. The ATO sets your reporting cycle based on your turnover:
- Quarterly — the default for most small businesses and sole traders, including most tradies.
- Monthly — required if your GST turnover is $20 million or more (rare for a sole trader).
- Annually — available in limited cases, e.g. if you're voluntarily registered for GST below the $75,000 threshold.
BAS due dates for quarterly lodgers
| Quarter | Period | Due date |
|---|---|---|
| Q1 | 1 Jul – 30 Sep | 28 October |
| Q2 | 1 Oct – 31 Dec | 28 February |
| Q3 | 1 Jan – 31 Mar | 28 April |
| Q4 | 1 Apr – 30 Jun | 28 July |
If you lodge through a registered tax or BAS agent, you may be eligible for extended due dates — often an extra four weeks. Check with your agent if you use one.
Note: The Q2 due date (28 February) doesn't get the usual four-week deferral that other quarters sometimes attract, so it's worth diarising this one specifically — it catches a lot of tradies out over the summer break.
The BAS labels a typical sole trader tradie actually needs
The BAS form looks intimidating because it has dozens of labels, but most tradies only ever touch a handful of them:
- G1 – Total sales — your total business income for the period, including GST.
- 1A – GST on sales — the total GST you collected from customers (10% of your GST-exclusive sales).
- 1B – GST on purchases — the GST you paid on business expenses and can claim back (tools, materials, fuel, subcontractors, etc).
- G10 / G11 — capital and non-capital purchases, if you're using the full reporting method rather than simpler GST.
- PAYG instalment (T7/T11) — only relevant if the ATO has placed you on the PAYG instalment system, usually after your first full year of solid profit.
Your net GST amount is simply 1A minus 1B. If 1A is bigger, you pay the ATO the difference. If 1B is bigger — for example, after a quarter of heavy tool or ute purchases — the ATO refunds you the difference.
Step-by-step: how to prepare your BAS as a sole trader
Here's the process most sole trader tradies follow each quarter:
- 1. Gather every invoice you issued in the period, and total up the GST-inclusive amounts — this becomes your G1 figure.
- 2. Work out the GST you collected — for standard 10% GST sales, divide your GST-inclusive total by 11. This is your 1A figure.
- 3. Gather your business expense receipts — fuel, materials, tools, insurance, phone, subcontractor invoices — anything with GST included that relates to the business.
- 4. Work out the GST you paid on those expenses the same way — divide the GST-inclusive total by 11. This is your 1B figure.
- 5. Calculate your net GST — 1A minus 1B is what you owe (or what's refunded to you).
- 6. Check for any PAYG instalment amount pre-filled on your BAS by the ATO, if you're on that system.
- 7. Lodge through the ATO's Online Services for Business, the ATO app, or your registered tax agent, and pay by the due date.
The step most tradies find painful is steps 1–4 — chasing down every invoice and receipt from a busy quarter. This is exactly where using a proper free invoice app for tradies pays for itself: every invoice is stored with its GST already broken out, so your G1 and 1A figures are ready without any manual adding-up.
Tip: Set aside GST as you go, rather than treating it as part of your cash flow. A simple rule of thumb is to move 1/11th of every GST-inclusive payment you receive into a separate savings account, so the money is already there when your BAS is due.
What records do you need to keep for your BAS?
The ATO requires you to keep records supporting every figure on your BAS for at least 5 years. For a sole trader tradie, that typically means:
- Copies of every Tax Invoice you issue — see our guide on what must a Tax Invoice include to make sure yours are compliant
- Receipts and Tax Invoices for every business expense you claim GST on
- Bank statements showing business income and expenses
- A record of any private-use portion of mixed expenses (e.g. a ute used for both work and personal trips)
Digital records are fine, and in most cases easier — a cloud-based invoicing app keeps everything in one place automatically, rather than relying on a shoebox of paper receipts.
Common BAS mistakes sole trader tradies make
1. Reporting GST-inclusive amounts as GST-exclusive (or vice versa)
Mixing up whether a figure includes GST or not is the single most common BAS error. Always double-check whether the number in front of you is the GST-inclusive total or the pre-GST price before you enter it.
2. Forgetting to claim GST credits on business expenses
Many sole traders under-claim 1B simply because they don't keep receipts for smaller purchases — fuel, hardware store runs, phone bills. These add up over a quarter and reduce what you owe.
3. Missing the due date
Late lodgement can attract a Failure To Lodge penalty, and interest accrues on any GST paid late. Even if you can't pay the full amount by the due date, lodge on time and contact the ATO about a payment plan — lodging late is generally penalised more heavily than paying late.
4. Not accounting for private use of a vehicle or tools
If you use your ute or tools for both work and personal use, you can only claim the GST on the business-use portion. Estimating this honestly avoids problems if the ATO reviews your BAS later.
5. Lodging a "nil" BAS late — or not lodging at all
Even if you had no sales in a quarter, you still need to lodge a nil BAS by the due date. Skipping it because "there's nothing to report" can still trigger a late lodgement penalty.
Make BAS time a non-event
TradesBill tracks GST on every invoice automatically and gives you a ready-to-use Tax Summary report — G1 total sales, GST collected, and your BAS figures for any quarter, in seconds.
Try TradesBill freeFrequently asked questions
Do I need an accountant to lodge my BAS?
No — you can lodge it yourself through the ATO's Online Services for Business or the ATO app. Many sole traders do their own BAS, especially once they have a system for tracking GST on invoices and expenses. That said, a registered BAS or tax agent can be worth it if your affairs are more complex, or you'd simply rather not deal with it.
What happens if I lodge my BAS late?
The ATO can apply a Failure To Lodge (FTL) penalty, which increases the longer the statement remains outstanding, plus general interest charges on any unpaid amount. If you're going to miss a deadline, contact the ATO before it's due — they're generally more lenient when you're upfront.
Can I do a BAS if I had no income that quarter?
Yes — and you still have to. This is called a "nil" BAS. You lodge it the same way, entering zero for your sales and GST labels, by the normal due date.
What's the difference between GST and PAYG instalments on a BAS?
GST is the tax you collect on sales and pay on purchases — it's not really "your" money, you're just collecting it for the ATO. PAYG instalments are prepayments toward your own income tax bill, based on your expected annual profit. Not every sole trader is on the PAYG instalment system — the ATO adds you once your income reaches a certain level.
Can TradesBill lodge my BAS for me?
No — TradesBill isn't a registered tax agent and doesn't lodge BAS statements on your behalf. What it does is track GST on every invoice you create and generate a Tax Summary report with the figures you need, so preparing and lodging your own BAS (or handing it to your accountant) takes minutes instead of hours. Read more about how to calculate GST on an invoice if you want the underlying formulas.