Solar Plan LabUnderstand it before you buy it
Build my plan
Interactive planning tool

Solar panel sizing calculator

Estimate array capacity, panel quantity, expected generation, and how the recommended panels can be connected into PV strings.

No account Instant result Explanation included
1Tell us what you knowStart with the fields you already understand.
2See the recommendationSee the number and why Solar Plan Lab suggested it.
3Refine or downloadChange the plan before you buy or download anything.
New to solar? You do not need to choose a calculator first. Build a guided home solar plan →
Inputs

Start with energy use

The simple view uses practical defaults for panel size, losses, and string layout.

1

For a first estimate, monthly kWh is enough. Solar Plan Lab starts with the saved sunlight assumption (4.5 peak-sun-hours/day by default). Open Advanced only when you want to change location assumptions, panel rating, string layout, or mounting.

i
Interactive visual aid

Solar panel array and connection diagram

-

-

Series connectionPanel voltages add together from positive to negative.
Parallel stringsString currents combine at the combiner or isolator.
DC protectionEach string needs correctly rated isolation and protection.
Inverter MPPTString voltage must remain inside the inverter operating limits.