Portable Solar Panel Payback Calculator: When Does Your Solar Panel Pay for Itself?

Calculate the break-even point and ROI of a portable solar panel based on your average daily usage, local sun hours, electricity rate, and panel cost. See how fast it pays off.

Mathematical Audit

How Solar Panel Payback Is Calculated

Payback period = upfront cost divided by annual electricity savings. Savings depend on panel wattage, daily peak sun hours, and local electricity rate.

Daily kWh Generated = Panel Wattage (W) × Peak Sun Hours ÷ 1,000
Annual kWh Generated = Daily kWh × 365 × System Efficiency (85%)
Annual Savings = Annual kWh × Electricity Rate ($/kWh)
Payback Period (years) = Panel Cost ÷ Annual Savings

Peak sun hours vary by location: US average 4–5 hours/day. Southwest US 6–7 hrs/day. Northeast US 3–4 hrs/day. Check NREL's PVWatts for your specific location.

Operational Guide

How to Use the Solar Panel Payback Calculator

1

Enter panel wattage and cost

From your panel's product specification (e.g., 100W panel for $120).

2

Set your peak sun hours

Average daily peak sun hours for your location. US average is ~4.5 hours.

3

Enter your electricity rate

From your utility bill in $/kWh (US average: $0.16/kWh).

4

Click Calculate

See daily generation, annual savings, payback period, and 10-year ROI.

Real-World Scenario Example

"A $200, 200W portable solar panel with 5 daily sun hours: generates 310 kWh/year × $0.16 = $49.60/year savings. Payback = 4.0 years. 10-year ROI: 148%."

Inputs

wattage:200
cost:200
sunHours:5
electricityRate:0.16

Result

Payback: 4.0 years | 10-year savings: $296 | ROI: 148%

Important Disclaimer

Energy generation estimates assume ideal conditions and an 85% system efficiency factor. Actual output varies based on panel angle, shading, temperature, and weather. This calculator is for planning purposes only.