Solar Panel Output Calculator

Estimate your daily, monthly, and yearly energy generation based on panel capacity and local sunlight.

System Specifications
Panel Rating (Watts) 400 W
Number of Panels 10
Peak Sun Hours / Day 5.0 hrs

National average is 4-5 hours. This is not total daylight!

System Efficiency 80 %

Accounts for inverter losses, wiring resistance, heat, and dirt.

AC
Total DC System Size
4.00 kW
Estimated AC Energy Output
16.0 Daily
kWh
480 Monthly
kWh
5,840 Yearly
kWh

How Solar Math Works

Calculating real-world solar output requires more than just multiplying the wattage sticker on the back of the panel. You have to account for local weather and physical electrical losses.

  • Peak Sun Hours: This is not the number of daylight hours. A "Peak Sun Hour" is one hour where the intensity of the sunlight reaches exactly 1,000 Watts per square meter. A location might have 12 hours of visible daylight, but only accumulate 4 "Peak Sun Hours" worth of intense, direct energy.
  • System Efficiency (The 80% Rule): Solar panels produce DC (Direct Current) power, but your home uses AC (Alternating Current). Converting DC to AC through an inverter loses about 10% of the power. Furthermore, solar panels actually lose efficiency when they get hot! Combined with voltage drop in the wires and dust on the glass, a standard safe estimate is an 80% efficiency rate.
  • The Formula: Total Capacity (kW) × Peak Sun Hours × Efficiency = Daily Energy (kWh)