Calculate your solar payback period

solar_choice_logo_finalSolar Choice has developed this payback and return on investment (ROI) calculator to help households throughout Australia make a decision about going solar.

However, it is important to keep in mind that the inputs and outputs below are to be taken as indicative only, and it does not take into account exactly how your home or business uses electricity throughout the day, the tilt & orientation of your roof, total system efficiency, or whether or not you would have any shading on your panels.

Were you looking for our Commercial Solar Payback Calculator?

Compare quotes from up to 7 installers in your area now.


Grab your energy bill and get started..

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Some notes on our calculations (if your interested!):

  • Sunlight hours are estimated based on data from Our assumptions for average per day Sunlight hours are Adelaide – 4.84, Brisbane – 5.16, Canberra – 4.78, Darwin – 5.92, Hobart – 3.83, Melbourne – 4.18, Perth – 5.34, Sydney – 4.54
  • GST is not charged on exported solar from residential systems
  • Calculator automatically adds 10% GST on retail electricity tariffs
  • We have assumed an overall system efficiency of 75% which is a conservative estimate
  •  ‘Years to pay off’, ‘Annual IRR’ and ‘System NPV’ output values all account for gradual panel degradation (from 97% of output based on nominal capacity in year 1, to 82% in year 25, as per panel manufacturer best practice.
  • This calculator works only for flat-rate tariffs. We are currently looking into building a similar tool for time of use and block tariffs.
  • At present, the calculator does not account for fixed daily ‘supply charges’ or electricity retailer discounts (e.g. ‘pay on time’ and ‘direct debit’ discounts).

Want a better Return on Investment?

We have written previously about how to get the most out of a solar PV system. Given the low value of excess/exported solar power in Australia (with rates in most states around 6-8¢/kWh), it is key to make sure that you’re consuming as much of the solar power your system produces as possible (read more about ‘solar self-consumption‘).

You should also be aware of how much you’re paying for grid electricity (‘Cost of retail electricity’) if you’re not sure or are considering switching your electricity retailer or tariff anyhow, visit the federal government’s EnergyMadeEasy website to compare rates on offer in your area, or check out Solar Choice’s Retail Electricity Plan Comparison Tool.

Additionally to ensure you get the most out of solar investment, sourcing a number of competitive solar quotes is important to making a well-informed decision. We have created Australia’s only online quote comparison tool with the objective of helping customers find good quality installers in their area. Enter your postcode below to get started.

Compare quotes from up to 7 pre-vetted installers in your area now.

Since 2008 our knowledge and sophisticated software has allowed over 160,000 Australian households and businesses to make a well-informed choice on their solar & battery installer.


Also see our new Solar Plus Battery Payback Estimator


  1. I am a sheep farmer and I am considering installing a solar system on a woolshed roof. Our electricity demand on our shed is reasonably low, approx $250/qtr, however at peak management times of the year like shearing time we have a very high and concentrated demand for approx 2-3 weeks where we are drawing high voltage and high amps, could you give some suggestions on how to work out the most efficient system to install on the shed. We would also consume the power in our house which is located approx 200 metres from the shed. I have used the calculator you provide however as I mentioned it is a bit tricky to input our peak amperage draw, thanks and regards George

  2. I currently have a 18 panel 3.2Kw system about 9 years old. I want to enlarge / renew the system, but have no more roof space. How large can I go with new panels?. My current PV was installed through your excellent services almost a decade ago. Note, my solar PV still pumps out heaps even after so many years.

  3. Grab your energy bill and get started..
    I could not Calculate my solar payback period as you do not have Cairns in the list.

    1. That is because Cairns is a hole that nobody cares about. Also, it says to pick your closest city. Brisbane would be the one you should select.

    2. Hi John,

      Unfortunately its tough to cater to everyone in Australia with this public calculator. Selecting Brisbane will be a reasonable estimate – otherwise I suggest you go through our comparison portal and our installer partners will be happy to put together a customer analysis for you.


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