Solar Calculators

Size your solar system, project 25-year savings, and understand the economics of going solar.

Calculate how many panels you need based on energy usage, location, and panel wattage.

25-year savings projection with inflation, degradation, and net metering.

Find the optimal panel tilt and azimuth for your latitude and seasonal needs.

Size your solar inverter correctly — string vs microinverter, DC/AC ratio, and clipping losses.

Size your solar DC wiring correctly — prevent voltage drop and energy loss.

Evaluate your roof's solar potential — orientation, tilt, shading, and usable area.

How many years until your solar panels pay for themselves? State-by-state estimates.

Find the average peak sun hours for your location — by state, city, or region.

Calculate how many panels per string and how many strings for your inverter.

Real-world vs rated panel efficiency — temperature, soiling, and system losses.

Not sure which calculator you need?

Start with the Energy Audit to see where your electricity actually goes.