This calculator works out array and panel count from daily energy and local peak sun hours. Daily energy is divided by local peak-sun hours and whole-system efficiency to produce a DC array size and panel count. Replace the example values with information from your own label, bill, drawing, product sheet or land record. Use site-specific solar resource, roof orientation, shading, inverter limits and an installer survey before procurement. The formula and every editable assumption remain visible so the result can be checked before it is used for planning. Keep the values and result together when you compare or share this planning scenario.
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Every input includes a simple explanation.
Private: calculations run in your browser. Saved scenarios, preferred electricity rate and land state stay on this device.
Motors and compressors can need extra power when they start.
Battery age, temperature and a high discharge rate can reduce delivered energy.
Use this as a planning range. Confirm continuous rating, peak rating and battery compatibility with the manufacturer and a qualified installer.
Read the meaning first, verify the important details, then avoid the most common planning error.
Daily energy is divided by local peak-sun hours and whole-system efficiency to produce a DC array size and panel count.
Use site-specific solar resource, roof orientation, shading, inverter limits and an installer survey before procurement.
Daylight hours are not peak-sun hours, and a shade-free noon does not prove full-day roof performance.
Updated 17 July 2026. Changes listed here describe this calculator release; they are not invented historical entries.