Solar Payback Calculator
Estimate how many years solar panels take to pay for themselves, from the system cost, your installer's generation estimate, how much you use and your tariffs.
- Free
- No sign-up to try
- Works as you type
Solar payback
Simple payback
11.9 years
Saving per year
$755
Generation per year
4,750 kWh
Net gain over those years
$9,875
- Generation = system size × yearly generation per kW.
- Saving per year = generation you use × your price + generation you export × export payment − upkeep.
- Payback = system cost ÷ saving per year.
- Net gain = saving per year × years − system cost.
Free, no sign-up to try. Save it as a live calculator you can share; an estimate from the numbers you enter, not a quote or financial advice. Check generation, prices and costs with your installer and supplier before you rely on it.
How it works
How the Solar Payback Calculator works
- 1
Enter your numbers
Every result updates as you type, with the formula shown under it.
- 2
Check the method
See how each number is worked out and what it assumes.
- 3
Save it as a Room
Share a live calculator: others can change the numbers and see the result update.
Worked example
What it makes
Example inputs
- System cost after any grants
- $9,000
- System size
- 5 kW
- Yearly generation per kW (your installer's estimate for your roof)
- 950 kWh/kW
- Share of the generation you use yourself
- 50 %
- Price you pay per kWh (your tariff)
- $0.28
- Payment per kWh you export (your tariff, 0 if none)
- $0.08
- Maintenance and insurance per year
- $100
- Years to count
- 25
Results
- Simple payback
- 11.9 years
- Saving per year
- $755
- Generation per year
- 4,750 kWh
- Net gain over those years
- $9,875
How it's calculated
- Generation = system size × yearly generation per kW.
- Saving per year = generation you use × your price + generation you export × export payment − upkeep.
- Payback = system cost ÷ saving per year.
- Net gain = saving per year × years − system cost.
- Assumes: Generation per kW depends on where you are, the roof's angle and shading: use the figure from your installer's quote or a solar estimate for your address.
- Assumes: Panels lose a little output each year and inverters often need replacing during the system's life; neither is included.
- Assumes: Prices stay at today's level and future savings are not discounted.
An estimate from the numbers you enter, not a quote or financial advice. Check generation, prices and costs with your installer and supplier before you rely on it.
Who it's for
Who uses it
Homeowners
Sense-check an installer's payback claim.
Small businesses
See what using more of the power yourself is worth.
Installers
Show a customer the assumptions behind a quote.
Good to know
What to consider
- Generation depends on location, roof angle and shading: use your installer's figure for your roof.
- Panel ageing and inverter replacement are not included. Not a quote or financial advice.
Questions
About the Solar Payback Calculator
Why does the share I use myself matter?
Power you use replaces electricity at your full price, while exported power usually earns much less. Enter both tariffs to see the difference.
Can I share the calculator with my team or a client?
Yes. The Room keeps the calculator live: anyone with the link can change the numbers and see the result update, with the method and assumptions on the same page.
Make your calculator now
Free, no sign-up to try. It becomes a Room you can edit, publish and share.
Create my calculatorRelated
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- NPV CalculatorWork out the net present value of an investment from the upfront cost and up to five years of cash flows at your discount rate, with the profitability index.