Solar Panel Array Sizing Calculator
Number of solar panels needed for a daily energy target.
Enter your values
ⓘ Live results
Results
- Panels needed
- 7 panels
- Array capacity
- 2800 W
- Daily energy from array
- 11.2 kWh
Quick answer
Panels needed = daily energy demand / (panel wattage x peak sun hours x system efficiency).
N = Ed / (W x PSH x eff)
How to use the Solar Panel Array Sizing Calculator
- 1Enter your daily energy requirement in kWh.
- 2Enter the wattage of the panels you plan to use and your location's peak sun hours.
- 3Apply a system efficiency factor for inverter and wiring losses, then round up to whole panels.
Worked example
Using the values the calculator loads with:
Inputs
- Daily energy need10 kWh
- Panel wattage400 W
- Peak sun hours5 hours/day
- System efficiency80 %
Results
- Panels needed7 panels
- Array capacity2800 W
- Daily energy from array11.2 kWh
Frequently asked questions
What are peak sun hours?
The equivalent hours per day of sunlight at 1000 W/m² intensity; check local solar irradiance maps.
Why include system efficiency?
Inverters, wiring, dust and temperature all reduce real-world output below the panel's rated wattage.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.