Solar panel calculator: count and system size
Enter your daily usage and panel wattage to see how many panels cover your needs.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter daily usage, peak sun hours, panel power, system efficiency after losses and area per panel.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
System size (kW) = daily kWh ÷ (peak sun hours × system efficiency). Panels = round up (system watts ÷ panel watts).
Example
Inputs: Daily usage = 30 kWh, Peak sun hours = 6 h/day, Panel power = 550 W, System efficiency after losses = 80 %, Area per panel = 2.6 m². Result: Number of panels: 12; Required system size: 6.25 kW; Installed capacity: 6.6 kWp.
Limits and caveats
- Peak sun hours vary by city and season, roughly 5 to 7 across most of the Gulf, so enter your local figure.
- 80% efficiency is a common allowance for heat, dust, wiring and inverter losses.
- Shading, tilt and orientation are not modeled.
Questions about this tool
How many panels do I need for 30 kWh a day?
With 6 peak sun hours and 80% efficiency you need 6.25 kW, which is 12 panels of 550 W.
What are peak sun hours?
The equivalent hours of 1,000 W per m² sunlight in a day, not the number of daylight hours.
Does this include batteries?
No, it sizes the panels only; use the solar battery size calculator for storage.