Electricity cost calculator
Watts, hours and your rate per kWh. See the cost per day, month and year.
- Runs in your browser — nothing you enter is uploaded
- No sign-up, no quotas, free to use as often as you like
How it works
Every appliance has a wattage on a label somewhere, and every bill has a rate per kilowatt-hour. Between them you can answer what something actually costs to run, which is usually either reassuring or startling and rarely what people guess.
Where to find the numbers
The wattage is on the rating plate, on the back or underneath, or in the manual. The rate per kWh is on your electricity bill — it is the single most important number here, and it varies more between suppliers and countries than any appliance does.
Rated watts versus actual
The plate shows maximum draw. Anything that cycles a thermostat — a fridge, a freezer, a kettle holding temperature, an air conditioner — spends much of its time drawing far less. For those, the yearly figure here is an upper bound. Things that run flat out, like a heater on full or a tumble dryer, are close to their rating.
Standby
Appliances left on standby draw a small amount continuously, and continuous small draws add up: one watt left on all year is about nine kWh. Enter 24 hours a day at a low wattage to see it.
The comparison worth making
Cost per hour of use is often the clearest figure. It is what lets you compare running a 2 kW heater for an hour against an hour of anything else, without doing arithmetic in your head.
Electricity cost calculator — questions
Where do I find my rate per kWh?
On your electricity bill. It is usually shown as a unit rate, separately from the standing charge.
Is the standing charge included?
No. This is the cost of the energy the appliance uses. The standing charge applies whether you use anything or not.
Why is my fridge cheaper than this says?
Because it cycles rather than running constantly. For thermostat-controlled appliances, treat the result as an upper bound.
What is a kWh?
One kilowatt drawn for one hour. A 1000 W appliance running for an hour uses exactly one.
Which currency is this?
Whichever you enter the rate in — the figures are plain numbers.