Solar Panel Sizing Calculator

Estimate the solar panel system size and cost for your home. Enter your electric bill and roof details to see how many panels you need, compare panel types, and calculate your payback period including the 30% federal tax credit.

Panel Type

Monthly Electric Bill ($)

Electricity Rate ($/kWh)

Roof Area Available (sq ft)

Peak Sun Hours

Pricing (edit to match local rates)

Standard ($/W)

Premium ($/W)

Budget ($/W)

Monthly Usage

1,154 kWh

13,846 kWh/year

Panels Needed

23 panels

8.8 kW system

Lowest System Cost

$15,426.69

After 30% ITC: $6,611.44 credit

Payback Period

10.3 years

403 sq ft roof needed

Panel Type	System Size	Cost (after ITC)
400W Standard	23 panels (8.8 kW)	$18,512.03
440W Premium	21 panels (8.8 kW)	$21,597.37
370W BudgetBest value	24 panels (8.8 kW)	$15,426.69

Lowest cost: 370W Budget at $15,426.69The 370w budget option requires 24 panels covering 420 sq ft of roof area. At your current electricity rate, the system pays for itself in approximately 8.6 years with annual savings of $1,800.00. The 30% federal Investment Tax Credit saves you $6,611.44.

Budget Panels: Lower Efficiency, More PanelsBudget panels are the cheapest per watt but require more roof space due to lower efficiency (18% vs 20-22%). Make sure you have adequate roof area. If space is tight, standard or premium panels may be necessary despite the higher per-watt cost.

This is an estimate for planning purposes. Actual system output depends on roof orientation, shading, local weather, inverter efficiency, and installer pricing. The 30% federal ITC applies to systems installed through 2032. Consult a licensed solar installer for a site-specific proposal.