Everyday

Electricity Cost Calculator

What this does

See what any appliance costs to run per day, month and year from its wattage and your electricity rate.

Enter your details

Runs in your browser

Calculator inputs

How to use it

Using the electricity cost calculator

  1. 01

    Find the wattage

    Check the appliance label, its spec sheet, or a plug-in power meter for the true draw.

  2. 02

    Estimate daily hours

    Be honest about actual runtime; a heater with a thermostat may run half the time it is switched on.

  3. 03

    Enter your rate

    Your bill’s price per kWh is printed near the usage totals; divide the supply-plus-delivery total by kWh if unsure.

Good to know

Heat is expensive; light is cheap

Anything that resists electricity to make heat; heaters, dryers, kettles; draws 1,500–5,000 W and dominates bills. LEDs draw under 15 W, so even leaving lights on rarely matters by comparison.

The delivery-charge surprise

Many bills split generation from delivery. Your true per-kWh cost is the sum of both, which can be double the advertised generation rate. Use the all-in figure here.

Idle load adds up

Devices drawing 5 W around the clock consume 44 kWh a year; small, but multiplied across a house full of chargers and set-top boxes it becomes a quiet line item worth killing.

How it's calculated

The math behind this calculator

kWh/day = watts × hours ÷ 1000 Cost/day = kWh/day × rate Month = ×30 days Year = ×365 days

A watt is already joules per second, so energy in kilowatt-hours is simply watts times hours divided by 1,000. Multiplying daily energy by your utility rate gives daily cost, which we extend to 30-day months and 365-day years.

Assumptions & limitations

  • Flat rate per kWh; time-of-use plans charge more at peak hours.
  • Steady power draw; devices with thermostats cycle on and off.
  • Standby (“vampire”) draw outside the entered hours is not counted.

Worked example

A 1500 W space heater running 6 hours a day at $0.15 per kWh burns 9 kWh daily; $1.35 a day, about $40.50 a month or $492.75 a year.

FAQ

Frequently asked questions

Where do I find my kWh rate?
It is itemized on your utility bill. Add supply/generation and delivery charges per kWh for the complete picture; US residential averages hover near $0.15–$0.17.
How do I measure an unknown device?
A plug-in power meter measures actual draw including standby modes, usually costing less than the savings it uncovers in a year.
Do old fridges really cost more?
Yes; pre-2000 refrigerators can draw two to three times as much as modern efficient units, making replacement one of the fastest energy paybacks in a home.

Keep exploring

Related calculators