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Trades & Construction Tax Utility

Tradie & Sole Trader GST Calculator

Designed for Australian sole traders, subcontractors, and tradies. Easily calculate GST on client quotes, deduct material expenses, and prepare your quarterly BAS.

construction

Tradie Job & BAS Calculator

Calculate GST on gross jobs, materials purchased at Bunnings/trade outlets, and subbie costs.

$

Total invoiced to residential/commercial clients.

$

Supplies bought at trade counters, Bunnings, Reece, etc.

$

Payments to GST-registered subbies hired for jobs.

$

Power tools, diesel/petrol, vehicle servicing, PPE gear.

BAS Label 1A (GST Collected) 1/11th of Invoiced Job Revenue
$1,000.00
BAS Label 1B (GST Credits) 1/11th of Materials + Subbies + Tools
$600.00
Estimated BAS Payable to ATO Label 1A minus Label 1B
$400.00
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Tradie Tip: Always make sure your quote clearly states whether the total figure is "Plus GST" (Exclusive) or "Inc. GST" (Inclusive) so clients aren't surprised when the final tax invoice arrives!

GST Essentials for Australian Tradies & Sole Traders

Running a trade business in Australia—whether you operate as a sole trader carpenter, electrician, plumber, painter, or general builder—comes with specific Australian Taxation Office (ATO) compliance obligations.

If your annual gross trade earnings reach or project to reach the ATO $75,000 threshold, registering for GST is mandatory. Once registered, you must add 10% GST to your labour rates and invoices while claiming back 1/11th GST credits on all business expenses incurred to perform your work.

Cash Basis vs. Accruals Basis: Which Accounting Method Should Tradies Use?

When registering for GST, the ATO allows sole traders and small businesses to choose between two reporting methods:

1. Cash Basis (Recommended for Tradies)

You only report GST in the quarter when cash actually enters or leaves your bank account. If you issue an invoice in September but the builder doesn't pay you until November, you don't owe the ATO GST until your Quarter 2 BAS.

2. Accruals Basis (Non-Cash)

You report GST in the quarter when the invoice or bill is issued, regardless of when payment is received. This can hurt cash flow if clients or head contractors delay paying invoices over 60–90 days.

Claiming GST Credits on Subcontractors & Materials

In the construction and trade sector, major job costs consist of raw materials (timber, concrete, wiring, piping) and specialized subbies (plasterers, excavators, sparkies).

1. Subcontractor Invoices (Checking ABN & GST Status)

You can only claim 1/11th GST input tax credits on subcontractor invoices if the subbie is registered for GST and has provided a valid Tax Invoice containing their ABN.

Warning (No ABN Withholding): If a subcontractor fails to provide an ABN on an invoice over $75, the ATO requires you to withhold 47% of their payment and remit it directly to the ATO unless they qualify for a statement by a supplier exemption.

2. Materials & Supplies (The 1/11th Rule)

Whenever you buy building supplies at trade suppliers (Bunnings, Tradelink, Reece, Middy's), the gross total includes 10% GST. Use our reverse GST formula (Total ÷ 11) to extract the tax portion to claim on your BAS.

The $82.50 ATO Tax Invoice Rule

To claim input tax credits on trade purchases on your BAS:

  • Purchases $82.50 or less (Inc. GST): A simple register receipt, docket, or tax invoice is sufficient proof for the ATO.
  • Purchases over $82.50 (Inc. GST): You must hold a formal Tax Invoice displaying the supplier's business name, ABN, invoice date, item description, and explicit statement of GST included.

Sample Tradie Job Breakdown Table

Item Description Gross Amount GST Component BAS Statement Line
Bathroom Renovation Quote $16,500.00 $1,500.00 Label 1A (GST Owed)
Tiles, Plumbing & Supplies $5,500.00 $500.00 Label 1B (GST Credit)
Subie Electrician Invoice $2,200.00 $200.00 Label 1B (GST Credit)
Net BAS Tax Payable to ATO (1A minus 1B) $800.00 Payable

Check upcoming lodgement deadlines using our BAS Due Dates Calendar or check if specific materials are exempt using our GST-Free Items Database. Need help with the tool? Get in touch via our Contact Page.

Tradie Tax Guidance

Frequently Asked Questions

Common GST and BAS questions for Australian sole traders, contractors, and tradies.