Solar Panel Sizing Calculator
Use this interactive tool to estimate how many watts of solar panels you need for your RV, camping setup, cabin, solar generator, or off-grid power system.
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Quick Presets
Recommended Wattage
240W
Suggested Setup
2× 200W panels or 1× 400W
Configuration
Roof-mounted rigid panels
How to Use This Calculator
Start by selecting a preset that matches your use case, or enter your own daily watt-hour consumption. Adjust the sun hours based on your location — most of the US gets 4–6 peak sun hours per day.
The efficiency loss slider accounts for real-world factors like temperature, wiring losses, shading, and panel degradation. A 20% loss is a reasonable default for most setups.
The calculator provides a recommended total solar wattage and suggests a panel configuration. Use these numbers as a starting point, then explore our comparison guides to find the specific panels that match your needs and budget.