The NumberTrove library
Energy
calculators.
Turn watts, hours, electricity rates, battery size, and charging efficiency into useful cost and planning estimates. These tools help compare appliances, EV charging options, and solar projects.
Choose the right energy calculator
Use your local electricity rate where possible and separate the energy used from the price charged. Real results vary with tariffs, losses, weather, driving habits, and equipment efficiency.
Every tool is free, browser-based, and includes its formula, assumptions, and related calculators. Use the links below to start with the result you need.
Electricity cost calculator
Turn appliance power, usage, and your electricity rate into a clear cost.
EnergyAppliance running cost
Estimate what an appliance costs to run hourly, daily, monthly, and annually.
EnergyAir conditioner running cost
Estimate the energy cost of running an air conditioner.
EnergySpace heater cost
Estimate what a space heater adds to your electricity bill.
EnergyEV charging cost calculator
Estimate the cost of charging an electric vehicle at home.
EnergyEV charging time calculator
Estimate how long a charge will take from your battery size and charger power.
EnergyEV vs gas cost calculator
Compare the energy cost of driving electric with the equivalent gasoline cost.
EnergyHome EV charger sizing
Estimate the charging power and circuit size needed for your daily driving.
EnergySolar EV charging calculator
Estimate how much of your EV charging can be supplied by solar power.
EnergyEV battery degradation estimator
Estimate remaining battery capacity from age, mileage, and an annual degradation assumption.
EnergySolar payback calculator
Estimate simple payback from system cost and annual energy savings.
Energy