Electricity Cost Calculator
Enter a device's wattage (or amps and volts), how long it runs and your price per kWh to see what it costs to run per day, week, month and year.
This electricity cost calculator turns an appliance's power draw into a running cost you can plan around. Type the wattage, or flip to amps and volts if that is what the plate lists, set the hours per day and days per week, then enter your rate per kWh from the bill. It works as an appliance running cost and kwh cost calculator, showing the energy used and the money spent, so you can act as your own energy bill calculator before you buy or leave something switched on. Presets fill common wattages for a fridge, AC unit, heater, PC or LED bulb, and every figure updates as you type.
Appliance
Presets
Cost per month
$13.65
$163.80 per year · 1,000 W
- Energy per day
- 3 kWh
- Cost per day
- $0.45
- Cost per week
- $3.15
- Cost per year
- $163.80
One kilowatt-hour is 1,000 watts running for an hour. A 1,000 W device left on all day would add up fast, so the days-per-week slider matters as much as the wattage.
Real draw varies: fridges and air conditioners cycle on and off rather than pulling full watts the whole time, so use their yearly kWh label for a truer figure. Rates also change by tier and time of day.
How it works
- 1
Enter the power
Type the device wattage, or switch to amps × volts and let it work out the watts. Presets fill common appliances.
- 2
Set the usage
Slide the hours per day and days per week to match how you actually use it.
- 3
Add your rate
Enter your price per kWh from the utility bill and read the cost per day, week, month and year.
Instant & 100% private — nothing is uploaded
Every calculation runs locally in your browser. The income, balances and goals you enter stay on your own device and are never sent to a server — nothing is stored, logged or shared.
Frequently asked questions
- How do I work out the running cost of an appliance?
- Multiply the wattage by the hours it runs to get watt-hours, divide by 1,000 for kWh, then multiply by your price per kWh. A 1,000 W heater run 3 hours a day uses 3 kWh, which is 45 cents a day at a 15 cent rate. The calculator does this for every period at once.
- Where do I find my price per kWh?
- It is printed on your electricity bill, usually as a rate per kWh or per unit. Some plans have tiers or peak and off-peak rates, so use the one that matches when the device runs. Type your own number in the rate field rather than a default.
- The label shows amps, not watts. What do I enter?
- Switch the toggle to amps × volts and enter both. Watts equal amps times volts, so a 10 A device on a 120 V supply draws 1,200 W. Use 120 V for a typical US outlet or 230 V for the UK and most of Europe.
- Why is my fridge estimate higher than the real bill?
- A fridge or air conditioner cycles its compressor on and off instead of pulling full watts all day, so entering its plate wattage for 24 hours overstates the cost. For those, use the yearly kWh figure on the energy label and divide by 365 for a truer daily number.
- Does a standby or LED device cost anything to run?
- A little. A 10 W LED bulb left on 5 hours a day is about 18 kWh a year, only a few dollars, but many small always-on loads add up. Set a low wattage and long hours to see how standby draw lands over a year.
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