Enter the system size, the yearly yield for your area, the share you use yourself and the prices.
Formula
Savings = production × self-use share × purchase price + surplus × feed-in price
Worked example
A 3 kWp system producing 3,600 kWh, 60% used on site: about 490 a year, payback in 15 years at 7,500.
Frequently asked questions
What yield should I use?
Roughly 1,000 kWh per kWp in northern Europe and up to 1,500 in the south.
Why does self-consumption matter?
Electricity you use yourself saves the full purchase price; surplus usually sells for much less.
Are price rises included?
No, this is a simple estimate.
Related calculators
Results are estimates for information only. Check important figures with a professional.