Electricity Calculator

Wattage, hours of use, and your electricity rate — monthly cost and kWh.

W
hrs
$/kWh

The average US residential rate is around $0.13/kWh — check your utility bill for the actual rate on your tariff.

Monthly cost
$46.80
kWh/day
12.000
kWh/month
360.0
Annual cost
$569.40

The power rating on a device is its maximum draw — actual consumption is often lower if the device uses variable speed, has standby modes, or cycles on and off.

A worked example

A 1,500W space heater running 8 hours/day at $0.13/kWh costs about $46.80/month.

The underlying electrical arithmetic has its own tools. Our Ohm's law calculator relates voltage, current and resistance, the resistor calculator reads colour bands, and the voltage drop calculator sizes cable over a run.

Frequently asked questions

What's a kilowatt-hour?

One kilowatt-hour is the energy used by a 1,000-watt device running for one hour — a 100W light bulb uses 1 kWh in 10 hours, while a 1,500W space heater uses 1.5 kWh per hour. It's the standard unit on electricity bills.

How do I find my electricity rate?

It's on your electricity bill, usually listed as a per-kWh charge. Rates vary significantly by utility, location, time of use, and season — the US average is around $0.13/kWh, but rates in some states run considerably higher.