Example 1: 6-panel rooftop system
Panel rating = 550 W, quantity = 6, sun hours = 5.5, system efficiency = 80%.
Array power = 550 x 6 = 3300 W = 3.3 kW
Daily energy = 3300 x 5.5 x 0.80 / 1000 = 14.52 kWh/day
Solar Panel Output Calculator
Use this online solar panel output calculator to estimate daily, monthly, and yearly solar energy production from panel wattage, panel count, peak sun hours, and system efficiency.
System efficiency can represent inverter loss, temperature loss, cable loss, dirt, mismatch, and other real-world derating effects.
Introduction
Solar panel output is usually estimated from the array peak power, the average daily peak sun hours for the location, and an overall efficiency or performance ratio. This gives a practical estimate of energy production rather than just the ideal nameplate rating.
This solar calculator is useful for rooftop solar systems, off-grid solar setups, and backup solar projects. It helps you estimate how much electricity a solar array can generate per day, per month, and per year under real-world operating conditions.
It is especially useful in early solar planning when users want a quick energy-production estimate from panel size, panel count, sun hours, and overall system performance.
Formula
Array peak power: Parr = Panel wattage x Number of panels
Daily energy: Eday = Parr x Peak sun hours x Efficiency / 1000
Monthly energy: Emonth = Eday x 30
Yearly energy: Eyear = Eday x 365
Daily energy: Eday = Parr x Peak sun hours x Efficiency / 1000
Monthly energy: Emonth = Eday x 30
Yearly energy: Eyear = Eday x 365
Variable Definitions
| Variable | Meaning | Typical Unit |
|---|---|---|
| Parr | Total installed panel nameplate power | W or kW |
| Peak sun hours | Equivalent full-sun hours per day | h/day |
| Efficiency | Overall delivered energy fraction after losses | % |
| Eday | Estimated daily energy production | kWh/day |
Units
Enter panel rating in watts, quantity as a whole number of panels, peak sun hours in hours per day, and system efficiency as a percentage.
Results are shown in kilowatt-hours, which is the standard unit used for solar generation, energy bills, and system yield comparisons.
Worked Examples
Example 2: 10-panel commercial array
Panel rating = 400 W, quantity = 10, sun hours = 4.5, system efficiency = 75%.
Array power = 4000 W = 4.0 kW
Daily energy = 4000 x 4.5 x 0.75 / 1000 = 13.50 kWh/day
Practical Solar Output Notes
Solar generation changes with season, weather, panel temperature, tilt angle, shading, and inverter efficiency. Because of that, real solar energy production can vary noticeably from the simple nameplate-based estimate. This solar panel output calculator is best used for comparing system sizes, estimating expected energy yield, and checking whether a planned PV array may cover part of a home, office, or battery charging load over time.