Free calculators

Energy calculators, powered by NREL data

Quick, single-purpose tools backed by the same public NREL datasets as the full modeler — solar production, irradiance, utility rates, and charging infrastructure for any location. No sign-up.

Solar payback calculatorPVWatts + Rates

Is solar worth it at your address? Real payback & 25-year savings, priced against your actual serving utility.

Solar production calculatorPVWatts

Estimate annual & monthly PV energy output for any location and system size — real NREL PVWatts solar resource.

Solar resource lookupNSRDB

Average GHI, DNI, and tilt-at-latitude irradiance for a US site, by month and annually.

Utility rate lookupUtility Rates

Average residential, commercial, and industrial electricity rates plus the serving utility for a US location.

EV charging & alt-fuel stationsAFDC

Find EV charging and alternative-fuel stations near a site — gauge readiness for fleet electrification.

Need the full picture? The Modeler sizes PV + battery + diesel and runs an hourly multi-year dispatch with lifecycle economics.