STC calculator
How many STCs is this job worth?
Enter the postcode, install date, panel size and battery size. It works out the certificates with the regulator's formulas, anywhere in Australia, for panels and batteries together.
Your job
Zone 4, rating 1.185
5 years of panel STCs, battery factor 6.8
0 if there are no panels on this job. Up to 100 kW.
0 if there is no battery. STCs stop at 50 kWh usable.
At $41 per STC
$5,330
130 STCs: 39 from panels, 91 from the battery
$195 more than at $39.50, the highest other price we found published on 3 November 2026
Open a trader accountAn estimate from the regulator's formulas, using the price we pay on a home system. We pay on the STCs the claim qualifies for, and systems and batteries must meet the eligibility rules.
How the sum works
Panels: kW x zone rating x deeming years, rounded down. Deeming years depend on the install year.
Batteries: usable kWh x factor, rounded down. The first 14 kWh count in full, 14 to 28 kWh at 60%, 28 to 50 kWh at 15%, and nothing above 50 kWh. The factor depends on the install date.
| Installed | Panel deeming years | Battery factor |
|---|---|---|
| May to Dec 2026 | 5 | 6.8 |
| Jan to Jun 2027 | 4 | 5.7 |
| Jul to Dec 2027 | 4 | 5.2 |
The four zones
A sunnier zone earns more STCs per kW. The calculator looks up the exact zone from the postcode, because the boundaries do not follow state lines. These are rough examples only.
| Zone | Rating | Examples |
|---|---|---|
| 1 | 1.622 | Central Australia, including Alice Springs |
| 2 | 1.536 | Darwin and the north, including northern WA and western Queensland |
| 3 | 1.382 | Sydney, Brisbane, Perth, Adelaide, Canberra and much of inland and regional Victoria |
| 4 | 1.185 | Melbourne, Hobart and southern WA's coast |
FAQ
STC calculator questions
How many STCs does a solar system get?
System size in kW, times the zone rating for the postcode, times the number of deeming years for the install year, rounded down. A 6.6 kW system in Melbourne installed in 2026 gets 39 STCs: 6.6 x 1.185 x 5. The deeming years fall by one each January until the scheme ends with 2030.
How many STCs does a battery get?
Usable capacity in kWh, tapered above 14 kWh, times the factor for the install date, rounded down. The first 14 kWh count in full, 14 to 28 kWh at 60% and 28 to 50 kWh at 15%. The factor is 6.8 for May to Dec 2026.
What is my postcode's zone?
Type the install postcode into the calculator. It uses the federal zone table, which sets a zone for every postcode range in Australia.
Does it cover hot water?
No. Solar water heaters and heat pumps get STCs by model and zone rather than by size, so this calculator leaves them out.
What dollar figure does it use?
$41 per STC, the price we pay on a home system as at 3 November 2026. The market moves, so check the date on any STC price.
Sources
Checked on 3 November 2026. An estimate only. The regulator decides what a claim is entitled to.
- Zone ratings and postcode zones for solar systems (federal instrument F2019L01583)
- Panel certificates fall each January (Clean Energy Regulator)
- Battery certificate factors to 2030 (Renewable Energy (Electricity) amendment regulations)
- Solar batteries: eligibility (Clean Energy Regulator, updated 29 October 2026)
- Create STCs: documents, audit and fees (Clean Energy Regulator, updated 2 November 2026)
Get paid 1 business day after approval
Open an account and send us one job to see how it goes. There is no cost, lock-in or minimum.