Solar kWh Calculator

Calculate estimated solar kWh production from solar system size, panel wattage, number of panels, peak sun hours, system losses, and electric rate. Use this solar kWh calculator to estimate daily solar kWh, monthly solar kWh, annual solar kWh, solar savings, roof space, and production coverage.

Calculate Solar kWh

Solar kWh = Solar System kW × Peak Sun Hours × System Efficiency.
Your result will appear here.

How the solar kWh calculator works

System size mode:
Enter a solar system size in kW to estimate daily, monthly, and annual solar kWh production.

Panel count mode:
Enter the number of panels and panel wattage to calculate system size and solar kWh output.

Single panel mode:
Estimate how many kWh one solar panel may produce per day, month, and year.

Target kWh mode:
Enter a target daily or monthly kWh amount to estimate the system size and number of panels needed.

Why use a solar kWh calculator?

A solar kWh calculator helps estimate how much usable electricity a solar panel system may produce before sizing a system, comparing quotes, planning roof space, or estimating savings.

It can help compare daily solar kWh, monthly solar kWh, annual solar kWh, panel count, system size, roof space, energy coverage, monthly savings, annual savings, cost, and payback period.

What your result means

Your result shows estimated solar kWh production for the day, month, and year. It also shows estimated system size, panel count, total system watts, roof space needed, energy coverage, electricity savings, installed cost, incentive value, net cost, and payback period.

Solar kWh formulas

Frequently asked questions

What does solar kWh mean?

Solar kWh means kilowatt-hours of energy produced by a solar panel or solar system. It measures energy, not just power.

How do you calculate solar kWh?

Multiply solar system size in kW by peak sun hours and system efficiency. That estimates daily solar kWh. Multiply daily kWh by 30 for monthly output or 365 for annual output.

How many kWh does a solar panel produce?

A 400-watt panel with 4.5 peak sun hours and 80% system efficiency may produce about 1.44 kWh per day, or about 43.2 kWh per month.

How many kWh does an 8 kW solar system produce?

An 8 kW system with 4.5 peak sun hours and 80% system efficiency may produce about 28.8 kWh per day, or about 864 kWh per month.

Is this solar kWh calculator exact?

No. This is an estimate. Real solar kWh output can vary based on location, shade, roof direction, roof angle, season, weather, panel temperature, inverter design, dirt, snow, and equipment performance.