How to quote a job with GST (Australia)
Step-by-step guide for tradies: when to add GST, ex-GST vs inc-GST pricing, markup vs margin, what to put on a quote, and a worked example.
1. Should you add GST at all?
Only charge GST if your business is registered for GST. You must register within 21 days once your GST turnover reaches $75,000 or more. That's your current month plus the previous 11 months, or the current month plus the next 11 months if you expect to reach it. Below the threshold, registration is optional. If you're not registered, don't add GST to your quotes.
If you should have registered and didn't, the ATO may make you pay GST on sales made since the date you were required to register, even if you didn't charge it, plus penalties and interest.
2. Work out the price ex GST first
- Materials: quantity × your cost × (1 + markup %).
- Labour: hours × your hourly rate.
- Other costs: delivery, equipment hire, tip fees, permits.
Add these together to get the subtotal ex GST. If you're registered, GST is 10% of that subtotal, and subtotal + GST = total.
3. Markup isn't margin
A 20% markup on cost isn't a 20% margin. If materials cost you $100 and you add 20%, you sell them for $120, and your margin is $20 ÷ $120 = 16.7%. To get a 20% margin you'd need a 25% markup ($100 → $125). Decide which number you actually care about.
4. Say clearly whether the price includes GST
Write "ex GST" or "inc GST" next to every price. If you only quote a GST-inclusive figure, the GST in it is 1/11 of the total. Mixing the two up is an easy way to end up in a dispute with a customer.
Worked example (made-up figures)
| Item | Calc | Ex GST |
|---|---|---|
| Steel, 4 lengths | 4 × $118.40 + 20% | $568.32 |
| Base plates & anchors | 8 × $22.50 + 20% | $216.00 |
| Consumables | $65 + 15% | $74.75 |
| Labour | 22 h × $95 | $2,090.00 |
| Delivery | 1 × $120 | $120.00 |
| Subtotal ex GST | $3,069.07 | |
| GST 10% | $306.91 | |
| Total inc GST | $3,375.98 | |
5. What to put on the quote
- Your business name, ABN and contact details (plus your licence number if your trade needs one).
- A quote number, the date, and a "valid until" date.
- The customer's name and the site address.
- The scope: what's included and, just as important, what's excluded.
- Line items or a clear price breakdown, the subtotal, GST and total.
- Payment terms and any deposit. Home building work has extra contract and deposit rules in each state, so check your state's building regulator.
6. A quote isn't a tax invoice
When the job is done, a GST-registered business issues a tax invoice. If a customer asks for one, you must provide it within 28 days, unless the sale is $82.50 (GST inclusive) or less. See what a tax invoice must show.
Free tools (they run in your browser):
Tradie Charge-Out Rate Calculator – work out the hourly and day rate that covers your wage, super, overheads and unbillable hours, plus profit, with or without GST
GST & BAS Quick Calculator – add or remove GST, estimate G1, 1A and 1B for a Simpler BAS, and check the $75,000 registration threshold.
Sources
Related guides
- What a tax invoice must show (Australia)
- Simpler BAS: what goes in G1, 1A and 1B
- Structural steel cut list basics: steel weight per metre formulas
- QBCC licence, the $3,300 threshold, contracts and deposits
- Do I need to register for GST? The $75,000 rule
General information only, summarised from the official sources above as at the review date. It isn't legal, tax, WHS or engineering advice. Rules change and your situation may differ, so check the source or ask a professional.