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Solar Payback Calculator Australia
Solar pays back through the electricity you do not buy and the power you export. How fast depends on what you paid, how sunny your roof is, how much you use during the day and what your retailer charges and pays. This calculator uses your figures for each and projects the saving year by year.
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From your installer's quote, after the small-scale technology certificates.
Varies by location from about 3.5 in the south to 5.5 or more in the north. Ask your installer for a figure for your roof.
Allows for heat, inverter loss and shading. 75% to 85% is typical.
The rest is exported. A household home during the day uses more.
From your bill, usage rate only.
What your retailer pays for exports.
Estimated payback
—Generation in year 1
—
Saving in year 1
—
Used at home
—
Exported
—
Net benefit over 25 years
—
Return on cost each year, year 1
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Cumulative cash position
An estimate, not a quote. An estimate from the figures you enter, not a quote or a forecast. Actual output depends on shading, orientation, equipment and weather, and tariffs, rebates and feed-in rates change. Compare quotes from accredited installers and check offers on Energy Made Easy.
How long does it take for solar panels to pay for themselves?
Divide the cost by the yearly saving: a 6.6 kW system costing $6,500 after rebates, generating about 8,094 kWh a year, with 40% used at home at 33c per kWh and the rest exported at 5c, saves around $1,311 in the first year and pays back in roughly 4.8 years. Your own tariff and usage will move that.
What drives the answer
The cost of the system after rebates, the sun on your roof, how much of the power you use yourself and the price you would otherwise pay decide the payback. A bigger system generates more but exports more too, so past a point the extra panels are paid at the lower feed-in rate.
The cost you enter should be the net price from a quote, after the small-scale technology certificates the installer deducts, not the sticker price.
Tariffs and feed-in
Retail plans differ in the usage rate, daily supply charge and feed-in rate, and some give a time-of-use rate that is cheaper in the middle of the day. Check your plan on your bill and compare offers on Energy Made Easy.
Feed-in rates have fallen over time, which makes using power yourself more valuable than exporting it.
To see what your bill is made of, use the electricity bill calculator.
How this is calculated
The rule, step by step, so you can check any figure by hand.
generation = system kW × peak sun hours × 365 × performancesaving = generation × self-use × your tariff + generation × (1 − self-use) × feed-in tariffeach year: generation falls by the degradation rate and the tariff rises by the price increasepayback = the year the cumulative savings equal the cost, interpolated within the year
Self-use is the most powerful lever: a kilowatt hour used at home saves the full usage rate, perhaps 30c or more, while an exported one earns the feed-in rate, often under 10c. Doubling self-use from 30% to 60% can shorten payback by years, which is why shifting the dishwasher, pool pump and hot water into the daytime matters.
The tariff rise is an assumption, not a promise. Setting it to zero gives a conservative payback, and the figure is shown so you can test it.
A worked example
A 6.6 kW system costing $6,500 after rebates, 4.2 sun hours, 80% performance, 40% self-use, 33c tariff, 5c feed-in, 3% tariff rise and 0.5% yearly output loss.
- Generation in year 18,094 kWh
- Value of power used at home$1,068
- Value of power exported$243
- Saving in year 1$1,311
- Payback4.8 years
- Net benefit over 25 years$35,645
Payback in about 4.8 years and a net benefit of about $35,645 over 25 years.
Batteries change the self-use figure and add cost; use your quote's numbers.
Batteries
A battery stores daytime generation for the evening, raising your self-use. Rebates and prices for home batteries change, and the payback of a battery often depends on the feed-in tariff and your evening usage. Test it by changing the self-use and the cost to match a battery quote.
What it leaves out
Inverter replacement, maintenance, finance costs and any change in your usage are not included. Panels are usually warrantied for 25 years, and inverters often need replacing around year 10 to 15.
What this calculator does not do
- A single-rate tariff; time-of-use plans need an average
- No inverter replacement or finance cost
- Output loss and price rises are constant assumptions
- Sun hours are your input, not a location lookup
Common questions
How long is the payback on solar in Australia?
Commonly between 3 and 7 years depending on the system cost, your tariff and how much power you use at home. Use your own quote and bill to find yours.
What is a feed-in tariff?
The rate your retailer pays for power you send to the grid, usually much less than you pay to buy it.
Does a battery shorten the payback?
Not usually by itself, because of its cost, but it can raise your self-use and reduce evening usage.
Do solar panels lose output over time?
Yes, slowly. About 0.5% a year is common, and the calculator allows for it.
Where can I compare offers?
Energy Made Easy, the Australian Government's comparison site, lists current retail offers for your postcode.
Where these numbers come from
- Clean Energy Regulator — small-scale renewable energy scheme How small-scale technology certificates reduce the upfront cost of a system
- Energy Made Easy Compare retail electricity offers for your postcode
- Your Home — Australian Government guide to sustainable homes Independent guidance on insulation, materials and design
Rates last verified 2026-10-26 Every figure Clean Energy Regulator sets is re-checked against the source at least once a year, and again whenever a change is announced. Out of date? Tell us and we will fix it.
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