Electricity Cost Calculator

Check the appliance's nameplate, spec sheet, or user manual — most list wattage directly, though some list amps and volts instead (multiply amps × volts to get watts). A plug-in power meter (like a Kill A Watt device) gives the most accurate real-world reading if the nameplate value seems approximate or the appliance's draw varies during use.

Electricity is billed in kilowatt-hours (kWh), not watt-hours — dividing wattage × hours by 1,000 converts from watt-hours to kilowatt-hours, matching the unit your electricity rate is quoted in on your utility bill.

Check your most recent electricity bill for the per-kWh rate (sometimes called the "energy charge") — rates vary significantly by region and utility provider, and some plans have tiered or time-of-use rates that differ by hour of day, which this simple calculator doesn't model.

No — it only calculates cost while the appliance is actively running for the hours you specify. Many electronics continue drawing a small amount of power even when "off" but plugged in; for a precise whole-appliance cost estimate, measure standby wattage separately and add it as its own 24-hour entry.