Solar panel payback calculator
What your system produces, how much it saves you and how many years until it pays for itself.
How it works
Production guide: ≈ 850-950 kWh/kWp in Belgium and northern France, up to 1,300 in the south. Gain = self-use × buy price + surplus × export price. Panels lose ≈ 0.5%/yr.
Results are for guidance only and do not replace professional advice.
Worked example
With the default values:
- System size (kWp)4.5
- Yearly production per kWp (kWh)900
- Self-consumed share (%)40
- Price of bought electricity (per kWh)0.32
- Price paid for exported power (per kWh)0.04
- System cost7200
you get:
- Savings per year€615.60
- Yearly production4,050 kWh
- Pays back in11.7 years
- Net gain over 25 years€7,301.04
Frequently asked questions
How does the “Solar panel payback calculator” tool work?
Production guide: ≈ 850-950 kWh/kWp in Belgium and northern France, up to 1,300 in the south. Gain = self-use × buy price + surplus × export price. Panels lose ≈ 0.5%/yr.
What do I need to enter?
Just fill in: system size, yearly production per kwp, self-consumed share, price of bought electricity, price paid for exported power, system cost. The result updates as you type.
Can you give an example?
System size (kWp): 4.5; Yearly production per kWp (kWh): 900; Self-consumed share (%): 40; Price of bought electricity (per kWh): 0.32; Price paid for exported power (per kWh): 0.04 → Savings per year: €615.60; Yearly production: 4,050 kWh.
Is this calculator free, and is my data private?
Yes. HOD Calc is completely free with no sign-up. The calculation runs in your browser: nothing you type is sent or stored.