STC calculator (Australia)
Estimate the small-scale technology certificates (STCs) for a rooftop solar system of up to 100 kW, and their value at a price you choose.
An estimate, not legal or financial advice. Formula: kW x zone rating x deeming period. Zone ratings are the Clean Energy Regulator (CER) values as of 1 January 2020. Deeming periods are from the CER page updated 18 September 2026. Rounded down to a whole STC (Regulations, reg 20(2A)(b)). The price is an input you choose. Check the official REC Registry calculator before you rely on a figure.
| Result | Value |
|---|---|
| Zone rating | - |
| Deeming period (years) | - |
| STCs before rounding | - |
| STCs (rounded down) | - |
| Value at the price above (AUD, before GST and fees) | - |
| STCs if installed one year later (same zone) | - |
Method: STCs = kW x zone rating x deeming period, rounded down. The CER clearing house pricing is capped at 40 AUD excluding GST (CER page updated 14 September 2026); the usual agent price on the CER consumer page (updated 18 September 2026) is 33 to 38 AUD. Systems above 100 kW fall under different mid-scale rules and are not calculated here. Home batteries use a separate calculation.