Appliance running cost calculator
Power rating, hours of use and your electricity price. That is enough to know what any appliance is really costing you.
Your figures
Result
- Cost per month
- $4.57
- Cost per day
- $0.150
- Cost per hour
- $0.150
- kWh per month (kWh)
- 30.4
- kWh per year (kWh)
- 365
- Hours of use per year (h)
- 365
By period
| Period | kWh | Cost |
|---|---|---|
| Per day | 1.00 | $0.15 |
| A la semana | 7.00 | $1.05 |
| Al mes | 30.44 | $4.57 |
| Per year | 365.25 | $54.79 |
What we assume
- The appliance is assumed to draw its rated power the whole time it is on. Anything with a thermostat — a fridge, a heater — cycles on and off and will use less.
- The electricity price should be the all-in price per kWh, including levies and tax. The figure on your bill is usually higher than the one in the tariff.
- Standing charges are not included: those you pay whether you use the appliance or not.
How it is calculated
Energy is power multiplied by time. Watts times hours gives watt-hours; divide by a thousand for kilowatt-hours, which is what you are billed in:
kWh = watts x hours / 1000
cost = kWh x price per kWh
The number that surprises people
Not the daily cost, which always looks trivial, but the yearly one. A 2,000 W heater on four hours a day is 8 kWh a day: pennies to think about, and several hundred over a winter. That is why we show all four periods at once.
Rated power is a ceiling, not an average
A fridge rated at 200 W does not draw 200 W continuously; its compressor runs perhaps a third of the time. For anything thermostatically controlled, use the yearly kWh from the energy label instead of the rating.
An example
A 2,000 W heater used 4 hours a day, 5 days a week at 0.15 per kWh costs 1.20 a day, about 26 a month, and roughly 312 a year.
Frequently asked questions
Where do I find the power rating?
On the label on the back or underneath, in watts (W) or kilowatts (kW). One kW is 1,000 W. If it only gives amps, multiply by the mains voltage.
Which electricity price should I use?
Take a bill, divide the total by the kWh consumed, and use that. It includes levies and tax, which the headline tariff usually does not.
Why does my fridge cost less than this says?
Because it is not running constantly. For appliances with a thermostat, use the annual kWh figure from the energy label rather than the power rating.
Keep calculating
All tools →- Standby power cost calculatorThe devices you never really switch off. Individually trivial, and together a line on your bill that nobody looks at.
- Is it worth replacing that applianceThe efficient one costs more today and less every year. Whether that trade works out depends on numbers, and usually it is closer than the shop suggests.
Updated on 2026-08-27. Calculations run in your browser; nothing you type is sent to a server.