Electricity Cost Calculator

Electricity rates vary by utility, tariff, season, time of use, taxes, and fixed charges. Enter the effective per-kWh rate from a recent bill for an estimate. The result does not model demand charges, tier changes, or fixed monthly fees unless they are already reflected in that rate.

Vampire load is electricity a device draws while plugged in but not actively in use, such as standby mode, idle chargers, or a smart speaker waiting for a wake word. The draw varies widely by device and settings. Use a plug-in meter or the product documentation for a meaningful estimate, then enter that wattage, your actual hours, and the rate from your bill.

Watts measure power, the rate at which a device consumes energy right now, while amps measure electrical current. The two are linked by voltage: watts = volts x amps. On a standard US 120V outlet, a 1,200W microwave draws 10 amps. Your electricity bill charges you for kilowatt-hours (kWh), not amps.

A kilowatt-hour is the energy a 1,000-watt device uses in one hour. Run a 100W light bulb for 10 hours and you consume 1 kWh. A 1,500W space heater running for two hours burns through 3 kWh. The calculator converts your wattage and daily hours into kWh to compute your cost.

The calculator applies the EPA eGRID 2022 U.S. average delivered-electricity factor of 0.394 kg of CO2 per kWh to your yearly energy use. Your actual figure depends on the power sources and transmission losses in your grid region.