Appliances & Utilities calculator
What Solar Panel System Size Do I Need?
Use your measurements for daily electricity need, average peak sun hours/day, and system output fraction to find solar panel array size.
Enter your measurements
Rather than guessing what solar panel system size do i need, enter daily electricity need, average peak sun hours/day, and system output fraction. The result is solar panel array size, calculated specifically for this product or space decision.
- Daily electricity need — Required
- Average peak sun hours/day — Required
- System output fraction — Required
Solar panel array size
Enter the measurements above to calculate solar panel array size.
How the calculation works
For this tool, the calculation is arrayPower=dailyEnergyUse/(peakSunHours×systemDerate). That produces solar panel array size without borrowing assumptions from unrelated calculators.
Worked example
Example: Daily electricity need = 8; Average peak sun hours/day = 4 h; System output fraction = 50%. Result: Array Power = 4 W.
Before you decide
Use measured dimensions rather than nominal labels. This page calculates the stated geometry or quantity only; product-specific construction or installation details can still affect the final choice. For what solar panel system size do i need, the limiting result on this page is solar panel array size.
Direct measurement/geometry calculation. No external reference is required for the arithmetic itself; the result is derived only from the user-entered measurements and the formula stored in calculationLogicJson.
Frequently asked questions
What does the Solar Panel System Size calculator tell me?
It returns solar panel array size from the measurements entered on this page. The calculation is specific to solar panel system size, so the result should be compared with the exact product or specification you are considering.
Which measurements should I take for solar panel system size?
Measure daily electricity need, average peak sun hours/day, system output fraction. Use clear, usable dimensions rather than nominal room or product labels.
Should I round the solar panel array size?
Keep the calculated value for comparison, then choose a real product that meets or stays within the returned solar panel array size while allowing for the clearances, tolerances or ratings shown by its manufacturer.