Calculate the number of solar panels needed to offset your electricity usage. Enter your monthly electric bill or kWh usage along with your average sun hours to determine the system size and number of panels for your home.
Enter Your Measurements
Results
Solar Panels Needed
19
panels
System Size
7.5
kW
Annual Production
11,096
kWh
Roof Area Needed
342
sq ft
Daily Target
30.0
kWh
Formula
How to Use This Calculator
How to Use
- 1
Find your monthly electricity usage in kWh from your utility bill.
- 2
Enter the average peak sun hours for your location (check NREL's PVWatts for your area).
- 3
Enter the wattage of the solar panels you plan to use (350-450W is typical for modern panels).
- 4
Set the desired offset percentage (100% to eliminate your electric bill).
Frequently Asked Questions
Frequently Asked Questions
How many solar panels for a 2000 sq ft house?
How much roof space do I need for solar panels?
How much do solar panels save per month?
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About This Calculator
This calculator uses the formula: System Size kW = (Monthly kWh ÷ 30 × Offset%) ÷ (Sun Hours × 0.8 efficiency) | Panels = System Watts ÷ Panel Watts. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
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