Free calculator library
Turn energy questions into numbers.
Every tool shows its assumptions and works without an account. Start with the inputs you already have.
Electricity Cost Calculator
Calculate any device from watts, runtime, schedule, and price per kWh.
Open calculator →CoolingAir Conditioner Cost
Use BTU capacity, EER, compressor runtime, and cooling days.
Open calculator →TransportationEV Charging Cost
Estimate wall energy and cost from miles driven and vehicle efficiency.
Open calculator →HeatingSpace Heater Cost
See how 1,500 watts and daily runtime translate into a winter bill.
Open calculator →OutdoorPool Pump Cost
Model pump wattage, daily schedule, and local electricity price.
Open calculator →Whole homeMonthly Bill Estimator
Convert household kWh, price, and fixed charges into a bill estimate.
Open calculator →DiagnosticHigh Electric Bill Check
Compare two bills and separate changes in usage from changes in price.
Open calculator →HeatingHeat Pump vs Furnace
Compare the modeled electricity cost of a heat pump and an electric resistance furnace for the same monthly heating load.
Open calculator →Water heatingWater Heater Cost
Estimate electric water-heating energy and cost from hot-water volume, temperature rise, efficiency, and electricity price.
Open calculator →Always-on loadsStandby Power Cost
Calculate the monthly and annual electricity cost of devices that remain on or in standby around the clock.
Open calculator →Whole homeWhole-Home Usage
Build a monthly household electricity estimate by combining HVAC, water heating, appliances, lighting, EV charging, and other loads.
Open calculator →Backup powerBattery Runtime
Estimate backup-battery runtime from usable capacity, reserve setting, inverter efficiency, and average electrical load.
Open calculator →TransportationEV Cost per Mile
Calculate home-charging electricity cost per mile, per 100 miles, and per month from efficiency, charging losses, and local electricity price.
Open calculator →Electric billsTime-of-Use Cost
Estimate a time-of-use electricity bill from peak and off-peak consumption, rates, fixed charges, and a load-shifting scenario.
Open calculator →Backup powerGenerator Running Cost
Estimate generator fuel cost per hour, per outage, and per delivered kWh from consumption, fuel price, load, and maintenance allowance.
Open calculator →Need a device-specific starting point?