GST calculator for electricians (Australia)
Electrical work usually mixes labour, a call-out or service fee, and materials you buy and resell: cable, power points, switchboard parts, safety switches, smoke alarms and light fittings. If you're registered for GST, all of it is a taxable sale, including the materials you pass on to the customer, at the price you charge (with your markup), not the price you paid.
Worked example: a typical electrician invoice
| Item | Qty | Unit price (ex GST) | Line total |
|---|---|---|---|
| Call-out / service fee | 1 | $90.00 | $90.00 |
| Labour (hours) | 3.5 | $110.00 | $385.00 |
| Double power point (supplied and installed) | 4 | $28.50 | $114.00 |
| RCD safety switch | 1 | $89.00 | $89.00 |
| Smoke alarm, 240V interconnected | 2 | $74.50 | $149.00 |
| Subtotal (GST-exclusive) | $827.00 | ||
| GST (10% of the subtotal) | $82.70 | ||
| Total including GST | $909.70 | ||
Figures are an illustration, not suggested prices. GST is worked out on the subtotal and rounded to the cent (the ATO's "total invoice" rounding approach). Check: $909.70 ÷ 11 = $82.70.
GST credits sparkies commonly claim
If you're registered for GST, you can generally claim a GST credit for the GST in business purchases (the business-use share for mixed-use items), as long as you hold a tax invoice for purchases over $82.50 including GST. Common examples:
- cable, fittings and switchgear from the wholesaler (keep the tax invoice for anything over $82.50)
- test equipment and tools
- the business-use share of your ute or van running costs
- phone and software subscriptions used for the business
- licence renewals and insurance (check the invoice: some insurance includes GST, stamp duty does not)
Common GST mistakes
- Charging GST only on labour and not on the materials. If you're registered, the materials you supply are part of a taxable sale.
- Claiming GST credits on wholesaler invoices without a tax invoice. Under $82.50 a receipt is enough; above it, you need the tax invoice.
- Quoting "$1,200" without saying whether GST is included. Say "$1,200 + GST" or "$1,320 incl. GST".
Questions
Do I charge GST on materials I pass on at cost?
If you're registered for GST, yes. Materials you supply as part of the job are part of your taxable sale, whether or not you add a markup.
I'm under $75,000. Do I have to register?
Not for electrical work alone; registration is required at $75,000 GST turnover. Below that it's optional. If you're not registered, don't add GST and call your document an "Invoice", not a "Tax invoice".
The rules in one place
- GST is 10%. The GST in a GST-inclusive price is the price ÷ 11.
- You must register at A$75,000 GST turnover (current month plus the previous 11, or projected for the next 12), within 21 days. Taxi and rideshare drivers must register regardless of turnover.
- If a customer asks for a tax invoice, you must give one within 28 days, unless the sale is A$82.50 (incl. GST) or less.
- Quarterly BAS for FY2026-27 is due 28 Oct 2026, Tue 2 Mar 2027, 28 Apr 2027 and 28 Jul 2027 (calculator).
Sources (checked 17 Oct 2026): ATO Tax invoices (updated 18 Sep 2026); ATO Registering for GST; ATO When you can claim a GST credit.
General information, not tax advice. It doesn't take your circumstances into account. Check with the ATO or a registered tax or BAS agent.
Related
- Free printable invoice template for electricians · Full GST calculator · BAS due dates · PAYG instalments
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