About JouleIO
JouleIO provides free, accurate, and easy-to-use calculators for solar energy, home electricity costs, and electric vehicles. Our mission is to help homeowners, renters, and EV enthusiasts make data-driven energy decisions.
Our Tools
We offer 11 specialized calculators across three categories:
- Solar Calculators — Size your solar system, estimate savings, calculate payback periods, and determine battery backup needs.
- Energy Calculators — Find out how much your appliances cost to run, calculate LED savings, and estimate your carbon footprint.
- EV Calculators — Compare gas vs. electric fuel costs, calculate charging costs, and estimate EV range under real-world conditions.
Privacy First
All calculations run entirely in your browser. No data is sent to any server, no account is needed, and no personal information is collected. Your energy data stays on your device.
Accuracy
Our calculators use industry-standard formulas, EPA data, and real-world performance metrics. While we strive for accuracy, results are estimates intended for planning purposes. Always consult qualified professionals for precise assessments before making major energy investments.
Why "Joule"?
The joule (J) is the standard unit of energy in the International System of Units, named after physicist James Prescott Joule. Our name reflects our focus on helping you understand and optimize your energy usage — one calculation at a time.