Electricity cost calculator

Work out an appliance’s consumption and cost – per use, day, month and year. With standby and multiple devices.

Choose a device

Presets are typical guide values. The rating plate or manual of your own device is what counts.

Power (watts)

You will usually find the wattage on the rating plate or in the manual.

Number of devices

Whole numbers from 1 only.

Enter usage as

Electricity price (€/kWh)

Example value – enter your own unit price from your bill.

Include standby

Standby is the consumption while the device is not actively used – for example standby lights or power supplies.

Add standby costs

Standby consumption is included in the result only when this box is ticked.

Standby power (watts)

Standby hours per day

All entries stay in your browser.

How the electricity cost calculator works

The calculator multiplies your device’s power by the usage duration. Watts and hours give consumption in kilowatt hours; consumption and price give the cost.

Worked example

1,000 watts ÷ 1,000 × 2 hours × 365 days = 730 kWh per year. At €0.35 per kWh that is €255.50 per year.

Calculation assumptions

Consumption (kWh) = power (watts) ÷ 1,000 × usage (hours) × number of devices.
A year is calculated as 365 days and 52 weeks.
Standby is calculated separately and added to the total.
In appliances with a heater – washing machine, tumble dryer, dishwasher – the heater switches on and off during the programme. Wattage and runtime are therefore approximations; the kilowatt-hour figure on the energy label is authoritative.
For seasonal appliances such as air conditioners or fan heaters, spread the operating hours across the whole year, for example 500 hours per year as 10 hours per week.
All figures are rounded guide values. Variations due to measurement accuracy, tariff and usage patterns are normal.

Frequently asked questions

Where do I find wattage and electricity price?

The wattage is on the rating plate, in the manual or on the power supply. Your unit price in cents per kilowatt hour is on your electricity bill – 30 cents equals €0.30.

How do I convert minutes or single uses?

Enter the duration of one use in minutes and how often you use the device. The calculator converts minutes to hours and derives the annual consumption.

How is standby handled?

Active use and standby are calculated separately and then added. Standby power is often in the datasheet; typical values are 0.5 to 5 watts.

Why is the result only a guide?

Devices differ by model, age, temperature and usage. The power rating is a maximum or average figure. The result shows an order of magnitude, not your actual bill.