Australia solar calculator
Size a home solar system from your power bill — kW, panel count, cost after STCs, and payback with Australian feed-in tariffs.
Quick answer: At A$0.33/kWh and 4.8 peak sun hours, an A$250/month bill needs about 7 kW — 16 × 440 W panels covering ~32 m². STCs cut ~30% off the sticker price, landing the net cost near A$5,174 with a payback around 1.7 years.
Your details
Ballpark, not gospel. Sized at 78% real-world output with the Australian sun-hour average — confirm shading, roof orientation and your retailer's feed-in tariff with a local installer before buying.
Typical Australian system sizes by monthly bill
| Monthly bill | System size | Panels (440 W) | Net cost after STCs | Payback |
|---|---|---|---|---|
| A$150 | 4.40 kW | 10 | A$3,234 | 1.8 years |
| A$250 | 7.04 kW | 16 | A$5,174 | 1.7 years |
| A$400 | 11.00 kW | 25 | A$8,085 | 1.7 years |
Computed at A$0.33/kWh, 4.8 peak sun hours, A$1.05/W installed and a 30% STC reduction. Run your exact bill above.
Questions people actually ask
Straight answers, no fluff. Then run your own numbers above.
How many solar panels do I need in Australia?
At A$0.33/kWh and 4.8 peak sun hours, an A$250/month bill needs about a 7 kW system — roughly 16 × 440 W panels covering ~32 m² of roof.
What are STCs and how much do they save?
Small-scale Technology Certificates are a federal incentive created at install time — typically worth ~30% of the system price. On a 7 kW system costing A$7,392 gross, STCs cut about A$2,218, leaving A$5,174 net.
How much does solar cost in Australia in 2026?
About A$1.05 per watt installed before STCs — among the cheapest in the world. A 6.6 kW system runs roughly A$6,900 gross, A$4,830 net after STCs.
What is the payback period for Australian solar?
Often under 2 years on paper — an A$250/month bill saves A$3,000 a year against a A$5,174 net cost, paying back in ~1.7 years. Real bills vary with feed-in tariffs and self-consumption.
What is a feed-in tariff in Australia?
What your retailer pays you per kWh exported — typically 5–12 cents depending on state and retailer. Higher tariffs favour bigger systems; low ones favour batteries.
How much roof space does Australian solar need?
About 2 m² per panel including spacing. A 16-panel system needs roughly 32 m² of unshaded, north-facing (or east/west) roof.
How much CO₂ does Australian home solar avoid?
About 0.7 kg per kWh. A 7 kW system generating ~9,600 kWh a year offsets roughly 6.7 tons of CO₂ annually.
Should I add a battery to my Australian solar system?
If your feed-in tariff is under ~8c and you use power in the evening, batteries often beat exporting cheap and buying at 33c. Size the bank on the solar system calculator.
Batteries to beat low feed-in tariffs? The solar system calculator sizes your inverter and battery bank. Comparing quotes? The solar cost calculator breaks down cost per watt, and the solar ROI calculator maps your payback year by year.