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Enter the power of the device, how many hours a day it runs and what you pay per kilowatt-hour (kWh). The calculator shows the energy it uses and what that costs per day, per month and per year. It also works as a simple kWh calculator.

Enter your values

Printed on the device's label, in watts (W) or kilowatts (kW).
Where do I find this?

Look for a label or the manual: it shows W or kW. 1 kW = 1000 W.

If only volts and amps are given, multiply them: 230 V × 4 A = 920 W (the Watts to Amps Calculator does this).

Devices that cycle on and off, such as a fridge, use less than their label power on average: lower the hours accordingly.

How long it is switched on in an average day (0 to 24).
Where do I find this?

Think of a normal day: a TV on for 4 hours, a heater for 8.

For a device that runs all day but only draws full power part of the time, estimate the hours of full power, or measure it with a plug-in energy meter for a week.

From your electricity bill or contract.
Where do I find this?

On the bill look for 'price per kWh', 'energy price' or 'Arbeitspreis'.

If the price is in cents or pence, divide by 100: 32 ct = 0.32.

No price at hand? Divide the total of a bill by the kWh on it. This includes the fixed fees and gives a realistic all-in price.

Only changes the symbol; no exchange rate is applied.

Result

Enter your values to see the result.

Cost per month
– (30.4 days)
Cost per day
–
Cost per year
–
Energy per day
– kWh
Energy per month
– kWh
Energy per year
– kWh

Want this tracked for you? UtilityControl logs your meters and costs automatically.

How it is calculated

  • Energy per day (kWh) = power (W) ÷ 1000 × hours per day
  • Cost per day = energy per day × price per kWh
  • Per month = per day × 365 ÷ 12; per year = per day × 365

Example

A 1000 W heater running 4 hours a day uses 1000 ÷ 1000 × 4 = 4 kWh a day. At 0.30 per kWh that is 1.20 per day, about 36.50 per month and 438 per year.

What this estimate leaves out

The result is an estimate. It does not include standby power, fixed monthly fees, taxes that are not part of your price, or tariffs with different prices by time of day or by consumption.

Written and reviewed by QLines, Cologne · Last reviewed

FAQ

Frequently Asked Questions

How do I calculate the cost of running an appliance?

Divide its power in watts by 1000 to get kilowatts, multiply by the hours it runs to get kilowatt-hours (kWh), then multiply by your price per kWh. For example 2000 W for 1.5 hours is 3 kWh; at 0.30 per kWh that is 0.90.

What is a kilowatt-hour (kWh)?

A kilowatt-hour is the energy used by a 1000 W (1 kW) device running for one hour. It is the unit your electricity meter and your bill use.

Where do I find my price per kWh?

It is on your electricity bill or contract, often called energy price, unit rate or Arbeitspreis. If you only know the total of a bill, divide it by the kWh used to get an all-in price.

Why is my real bill different from the result?

The calculator covers one device and uses the average hours you enter. Your bill also contains the other devices, fixed monthly fees, taxes and possibly tiered or time-of-day prices.

More free calculators

Electricity Bill Calculator

Estimate your electricity bill from the kWh used, your price per kWh, a fixed fee and tax.

Watts to Amps Calculator

Convert watts to amps or amps to watts for DC, single-phase and three-phase circuits.

Track your meters instead of calculating by hand

UtilityControl keeps your readings, usage and costs for every meter and location, and it starts free.

See UtilityControl Pricing