Electricity Cost Calculator
Quick answer
Running cost equals watts ÷ 1000 × hours used × price per kWh. A 2,000 W heater for 5 hours a day at €0.25/kWh costs €2.50 a day.
Appliance running cost
On the rating plate. Amps × volts if only those are shown.
Cost per day
2.50
Per month (30 days)
75.00
Per year
912.50
Thermostatic appliances (fridges, heaters) cycle on and off, so real use is often 30–60% of the rated wattage.
Electricity is billed in kilowatt-hours: one kilowatt drawn for one hour. Every appliance carries a wattage on its rating plate, so the only arithmetic needed is converting watts to kilowatts and multiplying by hours and price.
The results usually surprise people in both directions. Heating and cooling dominate almost every bill, while the devices people worry about — phone chargers, LED bulbs — are close to irrelevant.
Where the money actually goes
Anything that makes heat or moves it is the expensive category: electric heaters, immersion heaters, tumble dryers, ovens, kettles and air conditioning. These draw between 1,000 and 3,000 watts, so a few hours a day adds up to a substantial share of a household bill.
Electronics are the cheap category. A laptop draws 30 to 65 watts, an LED bulb 5 to 10. Running a laptop eight hours a day for a month costs roughly what a tumble dryer costs in two or three cycles.
Standby, and whether it still matters
Standby power used to be a real cost when devices drew five to ten watts each. EU regulation has pushed most modern equipment below one watt, which across a household is typically a few euros a year rather than a few tens.
The exceptions are worth finding: set-top boxes, games consoles left in an instant-on mode, and older AV equipment can still draw ten to twenty watts continuously. Those are worth switching off; a phone charger is not.
Frequently asked questions
- Where do I find an appliance's wattage?
- On the rating plate, usually on the back or underside, or in the manual. If only amps and volts are listed, multiply them to get watts.
- Does an appliance always draw its rated wattage?
- No. Thermostatically controlled devices such as fridges, freezers and heaters cycle on and off, so real consumption is often 30 to 60 per cent of the rated figure over a full day.
- What is a typical price per kWh?
- It varies widely by country and tariff. Check a recent bill for your own figure — using an average from elsewhere can be off by a factor of two or more.
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Updated 2026-09-20 · all calculators. Results are estimates for guidance, not professional advice.