How do I calculate the cost to run an appliance?

Convert to kilowatt-hours — watts × hours of use ÷ 1000 — then multiply by your electricity rate. A 1,500 W space heater running 4 hours a day uses 6 kWh, which at $0.15/kWh costs $0.90 per day, about $27 a month.

What is a kilowatt-hour?

The energy of using 1,000 watts for one hour — the unit your utility bills you for. Ten hours of a 100 W device, one hour of a 1,000 W microwave, and 20 hours of a 50 W fan are each exactly 1 kWh.

Which appliances cost the most to run?

Heating and cooling dominate most bills, followed by water heaters, clothes dryers, and older refrigerators. Always-on "phantom" loads from electronics on standby can also add several percent to a typical household bill.

Why doesn't my bill match the calculation?

Utility bills add fixed monthly charges, taxes, and delivery fees on top of the per-kWh energy rate, and some utilities use tiered or time-of-use pricing where the rate changes with usage or hour. Use your bill's effective rate — total cost ÷ total kWh — for realistic estimates.

How can I lower my electricity costs?

Target the big loads first: thermostat setbacks, a heat-pump or efficient HVAC service, water heater temperature at 120°F, and full loads in dryer and dishwasher. LEDs, smart power strips for standby loads, and shifting use to off-peak hours (on time-of-use plans) compound the savings.

Electricity Cost Calculator

Calculate monthly electricity bills from kWh usage and your local rate. See appliance-by-appliance cost breakdown and sa

Appliance Details

Power Consumption (Watts)

Hours Used Per Day

Days Used Per Month

Number of Appliances

Energy Efficiency Rating

Electricity Rate

Electricity Rate (per kWh)

Seasonal Variation (%)

Daily Cost

$1.30

10.80 kWh

Monthly Cost

$38.88

324.0 kWh

Annual Cost

$466.56

3888 kWh per year

CO₂ Emissions

1427 kg

Per year

Efficiency Savings

10.0%

Less efficient

How it works

An electricity cost calculator finds what running a device costs. Convert its wattage to kilowatts, multiply by the hours used to get kilowatt-hours, then multiply by your utility's price per kWh.

Running cost

Cost = (watts ÷ 1000) × hours × price per kWh

watts: device power draw
hours: time used
price: your electricity rate per kWh

Worked example

1,000 W appliance
5 hours/day, $0.15/kWh

Daily kWh = (1000 ÷ 1000) × 5 = 5
Cost = 5 × 0.15

$0.75/day (≈ $22.50/month).

Good to know

Always-on devices (fridges, routers) cost more cumulatively than their low wattage suggests — multiply by 24×30.
Check your bill for the real per-kWh rate, including delivery charges and time-of-use pricing.
Standby 'phantom' loads add up; switching off idle electronics trims the bill.