Electrical, Solar & Energy Calculators
14 free calculators for electrical, solar and energy.
Energy planning needs a few reliable conversions. These calculators cover watts to amps, wire size, voltage drop, generator size, battery runtime, solar system and battery size, solar output, solar payback and panel cost, electricity and EV charging cost, BTU needs and heat pump savings.
All Electrical, Solar & Energy calculators
How to get good results
These are planning tools. Wire sizes, breakers and installs must follow the National Electrical Code and local rules, and the work should be done or checked by a licensed electrician.
How to choose an electrical, solar or energy calculator
These tools cover everyday electrical sums and home solar planning: converting watts to amps, choosing wire size and checking voltage drop, sizing a generator or battery, estimating running cost, and working out what a solar system could produce and cost. They are for homeowners comparing options and for people planning a project who want numbers to discuss with an installer.
For solar, start with the Solar System Size Calculator and the Solar Panel Output Calculator, then look at money with the Solar Panel Cost Calculator and the Solar Payback Calculator. For circuits, the Watts to Amps Calculator, Wire Size Calculator and Voltage Drop Calculator work together. Running costs come from the Electricity Cost Calculator and the EV Charging Cost Calculator.
Prices, sun hours, losses and rates are all editable inputs, because they differ by place and change over time. Results are estimates only. Electrical work can be dangerous and is regulated, so have a licensed electrician check wiring and let a qualified installer confirm any solar design. See the Disclaimer. Our guides to solar panel cost per watt and how many solar panels you need give worked examples.