A small-scale technology certificate (STC) calculator needs only a few inputs. For solar panels, the number of STCs is system size in kW, times the Clean Energy Regulator zone rating, times the deeming period in years. A 6.6 kW system in zone 3 installed in 2026 earns about 45 STCs, worth about A$1,793 at the October 2026 market price of A$39.85. A 10 kWh home battery installed in 2026 earns about 68 STCs, worth about A$2,710.
The official calculator is the Clean Energy Regulator STC calculator. The tables below give the answer for common sizes without running it.
Source: Clean Energy Regulator; Demand Manager Certificate Report October 2026.
Key facts
- The Clean Energy Regulator rates postcodes into four solar zones: zone 1 is 1.622, zone 2 is 1.536, zone 3 is 1.382 and zone 4 is 1.185 MWh per kW per year (postcode zone ratings document, as of 1 January 2020, checked November 2026).
- The Clean Energy Regulator sets the deeming period for rooftop solar systems up to 100 kW at 5 years for 2026 installations and 4 years for 2027 installations, falling to 1 year in 2030 (page last updated 29 October 2026).
- STCs traded between A$39.85 and A$39.90 through October 2026 according to Demand Manager, and the Clearing House price is capped at A$40 excluding GST.
- A 10 kW solar system in zone 3 installed in 2026 earns 69 STCs (69.10 before rounding down), which falls to 55 for a 2027 installation, a loss of about A$558 at A$39.85.
- Under the Cheaper Home Batteries Program, a battery installed between 1 May and 31 December 2026 earns 6.8 STCs per usable kWh, with the first 14 kWh at 100 per cent, 14 to 28 kWh at 60 per cent and 28 to 50 kWh at 15 per cent.
- STC counts here are Solar Cobber calculations rounded down to whole certificates; the Clean Energy Regulator page does not print the rounding rule for solar or batteries, so the official calculator decides your exact count.
How do you calculate STCs for solar panels?
Multiply system size in kW by the zone rating and by the deeming period. A Small-scale Technology Certificate (STC) is a tradable certificate worth 1 MWh of expected generation, and the deeming period is the number of years of generation the scheme credits upfront.
Solar Cobber calculation, 6.6 kW in Sydney (zone 3), installed 2026: 6.6 x 1.382 x 5 = 45.61, which rounds down to 45 STCs. At A$39.85 each that is A$1,793. Installers usually pocket a trading margin, so the discount on your quote can be a little lower.
Your zone is set by postcode, not by city. Melbourne and Hobart are zone 4, Darwin is zone 2, Alice Springs is zone 1, and Sydney, Brisbane, Adelaide, Perth, Canberra and Cairns are zone 3 (looked up with each city’s central postcode in the Clean Energy Regulator table). Suburbs can differ, so check your postcode on the regulator’s zone table.
How many STCs do you get for each solar system size?
A 6.6 kW system earns 45 STCs in zone 3 in 2026 and 36 in 2027. The table shows certificates by size and zone for 2026 installations (5-year deeming), as calculated from the Clean Energy Regulator ratings.
| System size | Zone 1 | Zone 2 | Zone 3 | Zone 4 |
|---|---|---|---|---|
| 3 kW | 24 | 23 | 20 | 17 |
| 4 kW | 32 | 30 | 27 | 23 |
| 5 kW | 40 | 38 | 34 | 29 |
| 6.6 kW | 53 | 50 | 45 | 39 |
| 8 kW | 64 | 61 | 55 | 47 |
| 10 kW | 81 | 76 | 69 | 59 |
| 13 kW | 105 | 99 | 89 | 77 |
| 15 kW | 121 | 115 | 103 | 88 |
| 20 kW | 162 | 153 | 138 | 118 |
The same systems installed in 2027 (4-year deeming) earn fewer certificates, as this table shows.
| System size | Zone 1 | Zone 2 | Zone 3 | Zone 4 |
|---|---|---|---|---|
| 3 kW | 19 | 18 | 16 | 14 |
| 4 kW | 25 | 24 | 22 | 18 |
| 5 kW | 32 | 30 | 27 | 23 |
| 6.6 kW | 42 | 40 | 36 | 31 |
| 8 kW | 51 | 49 | 44 | 37 |
| 10 kW | 64 | 61 | 55 | 47 |
| 13 kW | 84 | 79 | 71 | 61 |
| 15 kW | 97 | 92 | 82 | 71 |
| 20 kW | 129 | 122 | 110 | 94 |
- Installed 2026
- Installed 2027
Source: Solar Cobber calculation from Clean Energy Regulator zone ratings and deeming periods, checked November 2026. Size x 1.382 x deeming years, rounded down.
View the data as a table
| Installed 2026 | Installed 2027 | |
|---|---|---|
| 3 kW | 20 | 16 |
| 4 kW | 27 | 22 |
| 5 kW | 34 | 27 |
| 6.6 kW | 45 | 36 |
| 8 kW | 55 | 44 |
| 10 kW | 69 | 55 |
| 13 kW | 89 | 71 |
| 15 kW | 103 | 82 |
| 20 kW | 138 | 110 |
Every size loses 20 per cent of its certificates when the deeming period drops from 5 to 4 years on 1 January 2027, so a 10 kW system in zone 3 falls from 69 to 55 STCs.
What is an STC worth in dollars?
An STC is worth about A$39.85 as at October 2026. Demand Manager’s October 2026 certificate report says STCs traded between A$39.85 and A$39.90 and that 522,000 certificates changed hands. The Clean Energy Regulator Clearing House accepts certificates at A$40 excluding GST, which acts as the price ceiling. We found no November 2026 quote we could open, so these figures use the October price.
| System size | Zone 3, 2026 | Zone 3, 2027 | Zone 4, 2026 | Zone 4, 2027 |
|---|---|---|---|---|
| 3 kW | A$797 | A$638 | A$677 | A$558 |
| 4 kW | A$1,076 | A$877 | A$917 | A$717 |
| 5 kW | A$1,355 | A$1,076 | A$1,156 | A$917 |
| 6.6 kW | A$1,793 | A$1,435 | A$1,554 | A$1,235 |
| 8 kW | A$2,192 | A$1,753 | A$1,873 | A$1,474 |
| 10 kW | A$2,750 | A$2,192 | A$2,351 | A$1,873 |
| 13 kW | A$3,547 | A$2,829 | A$3,068 | A$2,431 |
| 15 kW | A$4,105 | A$3,268 | A$3,507 | A$2,829 |
| 20 kW | A$5,499 | A$4,384 | A$4,702 | A$3,746 |
Values are STC count multiplied by A$39.85 (Solar Cobber calculation). Your installer sells the certificates and passes on the value as a lower price, so ask for the STC amount to be shown as its own line on the quote. Our STC explainer covers how the rebate is applied and who qualifies.
How much of a quote is the STC discount?
On a 10 kW system the STC discount is between 17 and 25 per cent of the price before the discount. Solar Choice’s November 2026 price index gives average installed prices that already include the STC discount, so adding the certificate value back gives the pre-discount price.
Solar Cobber calculation, 10 kW in Sydney: Solar Choice standard offer A$8,810 after the discount, plus 69 STCs x A$39.85 = A$2,750, gives about A$11,560 before the discount. The discount is A$2,750 divided by A$11,560, or 23.8 per cent.
Source: Solar Choice Solar Panel Price Index (1 November 2026 data); Clean Energy Regulator zone ratings; Demand Manager October 2026. Darwin is zone 2 and Hobart and Melbourne zone 4; the other cities are zone 3. Assumes the installer passes on A$39.85 per STC.
View the data as a table
| STC share of price | |
|---|---|
| Perth | 24.6% |
| Canberra | 24.3% |
| Adelaide | 24.2% |
| Sydney | 23.8% |
| Brisbane | 22.7% |
| Melbourne | 21.0% |
| Hobart | 17.5% |
| Darwin | 16.9% |
Perth, Canberra and Adelaide see about a quarter of the pre-discount price come off, while Darwin sees about 17 per cent because its installed prices are the highest in the index.
How many STCs does a home battery earn?
A 10 kWh battery installed in 2026 earns 68 STCs, and the same battery in 2027 earns 57. Since 1 May 2026 the Cheaper Home Batteries Program has tapered certificates by size: usable kWh up to 14 earn the full factor, kWh above 14 up to 28 earn 60 per cent, kWh above 28 up to 50 earn 15 per cent, and nothing is earned above 50 kWh (Clean Energy Regulator, 29 October 2026). The factor is 6.8 for May to December 2026.
Solar Cobber calculation, 20 kWh battery, 2026: the first 14 kWh x 6.8 = 95.2, plus 6 kWh x 60% x 6.8 = 24.5, a total of 119.7, which rounds down to 119 STCs, or about A$4,742 at A$39.85.
Our battery rebate guide lists the step-down schedule from the Department of Climate Change, Energy, the Environment and Water, which we last checked on 15 October 2026. The 2027 column below uses its 5.7 factor for January to June 2027; we could not reopen the department page on 14 November 2026 to recheck that figure, so confirm it before you buy.
| Usable capacity | STCs, 2026 (factor 6.8) | Value at A$39.85 | STCs, Jan to Jun 2027 (factor 5.7) | Value at A$39.85 |
|---|---|---|---|---|
| 5 kWh | 34 | A$1,355 | 28 | A$1,116 |
| 10 kWh | 68 | A$2,710 | 57 | A$2,271 |
| 13.5 kWh | 91 | A$3,626 | 76 | A$3,029 |
| 15 kWh | 99 | A$3,945 | 83 | A$3,308 |
| 20 kWh | 119 | A$4,742 | 100 | A$3,985 |
| 28 kWh | 152 | A$6,057 | 127 | A$5,061 |
| 30 kWh | 154 | A$6,137 | 129 | A$5,141 |
| 40 kWh | 164 | A$6,535 | 137 | A$5,459 |
| 50 kWh | 174 | A$6,934 | 146 | A$5,818 |
- 2026 (6.8)
- Jan to Jun 2027 (5.7)
Source: Solar Cobber calculation from Clean Energy Regulator battery tiers and the factor schedule in our battery rebate guide. Usable kWh in tiers 100%, 60% and 15% of the factor, rounded down.
View the data as a table
| 2026 (6.8) | Jan to Jun 2027 (5.7) | |
|---|---|---|
| 5 kWh | 34 | 28 |
| 10 kWh | 68 | 57 |
| 13.5 kWh | 91 | 76 |
| 15 kWh | 99 | 83 |
| 20 kWh | 119 | 100 |
| 28 kWh | 152 | 127 |
| 30 kWh | 154 | 129 |
| 40 kWh | 164 | 137 |
| 50 kWh | 174 | 146 |
A 50 kWh battery earns only about 2.6 times the STCs of a 10 kWh battery, so the discount per kWh falls from about A$271 at 10 kWh to about A$139 at 50 kWh. The Clean Energy Regulator calculator and your installer’s quote hold the exact figures; for what batteries cost before the discount, see how much a solar battery costs.
Does waiting until 2027 cost you?
Yes, on the certificates alone. A zone 3 6.6 kW system loses 9 STCs (about A$359) and a 13.5 kWh battery loses 15 STCs (about A$598) between 2026 and early 2027. Falling hardware prices can offset part of that, and certificate prices move, so compare quotes dated for the same installation window. The STC count depends on installation date, not quote date. For price context see our 5 kW and 10 kW solar price guides and what size solar system you need.
What to check on your quote
Look for the STC count and dollar value as a separate line, your zone and the installation date. Check that the system size matches the panel rating, that the installer is accredited and the products are on the approved lists. Compare installers in your area on our companies directory and read our guide to the federal solar rebate before signing.
FAQ
How many STCs do I get for a 6.6 kW solar system?
You get about 45 STCs in zone 3, 39 in zone 4, 50 in zone 2 and 53 in zone 1 if installed in 2026. The formula is 6.6 kW x zone rating x 5 years, rounded down. In 2027 the same system earns 36, 31, 40 and 42.
What is an STC worth right now?
An STC was worth about A$39.85 as at October 2026, according to Demand Manager. The Clean Energy Regulator Clearing House price is A$40 excluding GST. Your installer may pass on a little less after fees.
What zone is my postcode in?
Zones are looked up by postcode in the Clean Energy Regulator’s zone ratings table. Sydney, Brisbane, Adelaide, Perth and Canberra are zone 3, Melbourne and Hobart are zone 4, Darwin is zone 2 and Alice Springs is zone 1. Suburbs and regional postcodes can differ from their city.
Is the STC a cash payment?
No. The STC is a certificate that your installer sells, and the value usually appears as a lower price on your invoice. You normally assign the certificates to the installer when you sign.
Do batteries earn STCs?
Yes, under the Cheaper Home Batteries Program. A battery installed from 1 May to 31 December 2026 earns 6.8 STCs per usable kWh, tapered by size tier. A 10 kWh battery earns about 68 STCs.
Do STCs go down every year?
Yes. The solar deeming period falls by one year each year, from 5 years in 2026 to 4 in 2027 and 1 year in 2030. Battery factors now step down every six months.
Can I claim STCs on an existing system?
The STC calculator and eligibility rules depend on the installation date and the system being newly installed, so we cannot give a general answer. Ask the Clean Energy Regulator or an accredited installer about your specific case.
How do I work out STCs for a battery bigger than 14 kWh?
Apply the full factor to the first 14 kWh, 60 per cent to kWh from 14 to 28, and 15 per cent to kWh from 28 to 50. A 20 kWh battery in 2026 earns 119 STCs.
Sources
- Clean Energy Regulator: Calculate small-scale technology certificate entitlements, last updated 29 October 2026
- Clean Energy Regulator: Postcode zone ratings and zones for solar systems
- Clean Energy Regulator: Buy and sell STCs, last updated 14 September 2026
- Demand Manager Certificate Report, October 2026
- Solar Choice Solar Panel Price Index, November 2026
- CER small generation unit STC calculator
About this guide
Written by the Solar Cobber editorial team from independent desk research checked in November 2026. Solar Cobber is a free directory that may earn referral or advertising fees from installers; commercial relationships never affect our content. This is general information, not financial advice. Spotted an error? Tell us at /contact.
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