Electricity Cost Calculator

Calculate how much it costs to run an appliance per day, month and year from its watts, hours of use, standby power and your electricity rate per kWh.

Appliances

Enter the power from the label or the manual (in watts), how long the appliance runs and, optionally, what it draws on standby the rest of the time.

Electricity rate (per kWh)

Example value only: enter the price per kWh from your bill, in your currency. For instance, residential rates in Canada range from under 10 cents to over 30 cents per kWh depending on the province and the tier.

Cost per day: –
Cost per month: –
Cost per year: –
Energy per day: –
Energy per month: –
Energy per year: –
Standby cost per year: –

Estimate only. Real consumption depends on thermostats, duty cycles and settings; your bill may add delivery charges, fixed fees, taxes and tiered or time-of-use rates.

How to use the electricity cost calculator

For each appliance, enter a Name (optional), its Power (W), the Hours per day it runs and the Days per week it is used.
If it stays plugged in, add its Standby power (W): the tool counts it for every hour the appliance is not running.
Use Add an appliance for more rows and × to remove one. Each row shows its own energy and cost per month.
Enter your Electricity rate (per kWh) from your bill.
Read the Cost per day, Cost per month and Cost per year, the energy in kWh, and the Standby cost per year. Reset defaults brings back the two example appliances.

Everything is calculated in your browser.

The formula

Energy is power multiplied by time. Because rates are per kilowatt-hour, the watts are divided by 1,000:

kWh per week (running) = watts × hours per day × days per week ÷ 1,000
kWh per week (standby) = standby watts × (168 − running hours per week) ÷ 1,000
kWh per day = kWh per week ÷ 7; per year = kWh per day × 365; per month = per year ÷ 12
Cost = kWh × rate

Example: a 1,500 W space heater running 4 hours a day uses 1.5 kW × 4 h = 6 kWh per day. At 0.15 per kWh, that is 0.90 per day, about 27.38 per month and 328.50 per year. A 100 W television watched 5 hours a day, drawing 1 W on standby for the other 19 hours, adds 0.519 kWh a day. Together: 6.519 kWh a day, 2,379 kWh and about 356.92 a year, of which 1.04 is standby.

Where to find the numbers

Power: the rating plate or the manual gives watts, or volts and amps (watts ≈ volts × amps). The rating is a maximum: appliances with a thermostat or a compressor (refrigerators, freezers, heaters, air conditioners) cycle on and off, so enter the hours they actually run, not the hours they are plugged in. A plug-in energy meter measures real use best.
Standby: chargers, set-top boxes, game consoles and TVs often draw 0.5 to 10 W around the clock.
Rate: the price per kWh is printed on your bill. It is entered by you, not stored in this tool. As an example only, residential rates in Canada range from under 10 cents to over 30 cents per kWh depending on the province, the tier and the time of day. With tiered or time-of-use pricing, use the rate that applies when the appliance runs, or your average rate (total energy charges ÷ kWh billed).

Limits

The result covers energy charges only. Bills also include fixed monthly fees, delivery or transmission charges, regulatory charges and taxes, which change the total but not the cost of running one more appliance by much. Consumption also varies with seasons: a heater runs more in January than in April.

Frequently asked questions

How do I convert watts to kWh?

Multiply the watts by the hours of use and divide by 1,000. A 60 W bulb on for 10 hours uses 60 × 10 ÷ 1,000 = 0.6 kWh.

How much does it cost to run a 1,500 W heater?

It uses 1.5 kWh per hour. Multiply by your rate: at 0.12 per kWh it costs 0.18 per hour, at 0.20 per kWh 0.30 per hour.

Is standby power worth counting?

Often yes, because it runs all year. A device that draws 5 W on standby uses about 44 kWh a year, and a home can have dozens of them.

Why is my bill higher than the result?

The tool does not include fixed fees, delivery charges or taxes, and appliances you did not list (water heater, lighting, heating) usually use most of the energy.

How do I estimate a refrigerator?

Start from the yearly kWh on its EnerGuide or ENERGY STAR label: multiply by 1,000 and divide by 8,760 hours to get its average power, then enter that power with 24 hours per day. A label of 400 kWh a year gives about 46 W around the clock.