Use the electricity cost calculator to work out an estimated electricity cost for an electrical device. Enter the power in watts, how long you use it, how often, and your own electricity price – and you get an estimate per use, per day, per month and per year.
The result is based on your inputs. It is not a measurement and not a forecast of your electricity bill. The preset electricity price is only a starting value that you can change.
The result appears here after you click “Calculate cost”.
The calculation runs directly in your browser. No input is stored.
Understanding the result
- kWh per year is the amount of energy the device needs per year at your usage.
- Cost per year follows from that energy and the electricity price you entered.
- Cost per month and per day are averages: the yearly value divided by 12 or 365.
This is an estimated electricity cost. Your actual electricity bill may differ. The wattage on the rating plate is often the maximum power; many devices run at lower power part of the time, in which case the real cost is lower. Not included are standby consumption, fluctuating power, purchase and maintenance costs, and the standing charge of your tariff.
Formula & calculation
This is how the calculator works:
- kWh per use = watts ÷ 1000 × hours
- Cost per use = kWh per use × electricity price
- Uses per year = uses per week × 52
- kWh per year = kWh per use × uses per year
- Cost per year = kWh per year × electricity price
- Cost per month = cost per year ÷ 12
- Cost per day = cost per year ÷ 365
Example
A 1,000-watt device runs for 1 hour per use and is used 7 times a week. In this example we assume €0.30 per kWh.
- 1,000 W ÷ 1000 × 1 h = 1 kWh per use
- 1 kWh × €0.30 = €0.30 per use
- 7 × 52 = 364 uses per year
- 1 kWh × 364 = 364 kWh per year
- 364 kWh × €0.30 = €109.20 per year
- €109.20 ÷ 12 = €9.10 per month
The price of €0.30 per kWh is only an example value. Enter your own price from your contract or bill in the calculator.
How you can reduce electricity costs
- Measure instead of guessing: a plug-in power meter shows how much a device actually uses.
- Avoid standby: switch devices off completely after use or disconnect them with a switchable power strip.
- Check your usage: running time and settings (temperature, programme, brightness) directly affect consumption.
- Compare when buying: put the energy consumption figures side by side and run your expected usage through the calculator.
Related guides
Smart home guide
How smart technology is changing everyday life at home.
Smart lighting: Philips Hue, Nanoleaf or Ledvance?
Smart lighting systems compared.
Methodology & Sources
How we calculate, where information comes from, and what is an estimate versus a fact is explained on the Methodology & Sources page.