About the Electricity Cost Calculator
This electricity cost calculator works out the energy use (kWh) and running cost of every appliance in your home โ TV, refrigerator, air conditioner, space heater, gaming PC, EV charger and more. Add common appliances with one tap, include standby (vampire) power if you like, and the table shows which devices make up the biggest share of your electric bill.
How to use
- Enter your price per kWh. $0.17 is just an example โ divide your bill total by the kWh used to get your real effective rate.
- Tap appliance buttons to add them, or use + Add your own and type the wattage from the device label or manual.
- Adjust hours per day, days per month and quantity; each row shows its monthly kWh and cost instantly.
- Optionally tick Include standby power, then check the table for the biggest energy users. Your list is saved in this browser.
How to calculate the cost to run an appliance
kWh per month = watts ร hours per day ร days ร quantity รท 1,000
Cost = kWh ร price per kWh
Example: a 1,000 W space heater used 2 hours a day for 30 days uses 1,000 ร 2 ร 30 รท 1,000 = 60 kWh. At $0.17/kWh that is $10.20 a month and $122.40 a year.
Standby power is added for the hours the device is not running (720 hours in a 30-day month minus running hours).
Typical appliance wattage
| Appliance | Watts while running | Note |
|---|---|---|
| LED bulb | 5โ15 W | Replaces a 40โ100 W incandescent |
| Refrigerator | 30โ60 W average | The compressor cycles, so use the 24-hour average |
| TV (50โ65") | 80โ200 W | Standby usually under 1 W |
| Desktop PC | 100โ500 W | Much higher while gaming |
| Window / central AC | 500โ3,500 W | Inverter units draw far less once at temperature |
| Space heater | 750โ1,500 W | Often the biggest winter cost |
| Clothes dryer | 2,000โ5,000 W | Per load about 2โ5 kWh |
| EV Level 2 charging | about 7 kW | About 7 kWh per hour |
Actual values vary a lot; check the rating label or the EnergyGuide label.
What about tiered and time-of-use rates?
Many utilities charge different prices by usage tier or time of day and add fixed customer charges, delivery fees and taxes. This calculator uses a single price, so the most realistic input is your effective rate: total bill รท kWh used. If an appliance runs mainly at peak times or pushes you into a higher tier, its real cost can be higher.
FAQ
How do I find my price per kWh?
Look at your latest electric bill: divide the total amount by the kWh used. That effective rate includes delivery charges and taxes. The US residential average is roughly 17 cents per kWh, but it ranges from about 11 to over 40 cents depending on the state.
Why is the refrigerator set to 40 W for 24 hours?
A fridge's compressor switches on and off, so its average draw is far below the nameplate rating. Divide the annual kWh on the EnergyGuide label by 8,760 hours to get the average watts โ 400 kWh/year is about 46 W.
How much does standby power cost?
Most modern devices use under 1 W in standby, but cable boxes and older electronics can draw 5โ15 W. A constant 10 W is about 7 kWh a month, roughly $1.20 at $0.17/kWh. A switched power strip eliminates it.
How much does it cost to charge an electric car?
Multiply the kWh you add by your rate. A 7 kW home charger running 3 hours adds about 21 kWh; at $0.17 that is about $3.57, before charging losses of roughly 10%. Use the EV preset and adjust hours and days to match your driving.