How to use the Electricity Cost Calculator
- 1 Enter the appliance's power in watts.
- 2 Enter the hours used each day.
- 3 Enter how many you run.
- 4 Enter your rate in cents per kWh and read the cost.
Worked example
A 1,500 watt space heater used 6 hours a day at 18 cents per kWh. It uses 9 kWh a day, about 270 kWh a month. That costs about $1.62 a day, $48.60 a month and roughly $591 over a year.
Features
kWh and dollars
Energy and cost per day, month and year.
Any appliance
Space heaters, AC units, PCs, pool pumps and more.
Your rate
Uses the rate from your own bill.
When to use it
Space heaters
See the real cost of heating a room.
Home offices
Estimate computer and monitor costs.
Buying appliances
Compare efficient models.
Solar planning
Work out the usage solar would cover.
Frequently asked questions
How do I calculate electricity cost?
kWh = watts × hours ÷ 1,000. Cost = kWh × rate. A 1,500 W heater for 6 hours uses 9 kWh.
What is the average US electricity rate?
The residential average has been around 17 to 18 cents per kWh, but rates range from about 11 cents in some states to over 40 cents in Hawaii.
Where do I find my rate?
Divide your bill's energy charges by the kWh used, or check the rate on the bill.
Do appliances use power when off?
Many draw standby power, often 1 to 5 watts each.
How much does a space heater cost?
A 1,500 W heater costs about 27 cents an hour at 18 cents per kWh.
Does running at night save money?
Only if you are on a time-of-use plan with cheaper off-peak rates.
How much does central air cost to run?
A 3-ton central AC using about 3,500 watts for 8 hours a day costs about $5 a day at 18 cents per kWh.
How much does a refrigerator use?
A modern fridge uses about 400 to 600 kWh a year, roughly $6 to $9 a month at average rates.
What about charging an electric car?
An EV that drives 1,000 miles a month uses about 300 kWh, about $54 at 18 cents per kWh.
How can I lower my bill?
Use LED bulbs, smart thermostats, efficient appliances and turn off idle devices.
What is a time-of-use rate?
A plan where electricity costs more at peak times and less at night, rewarding shifted usage.
How do I find an appliance's watts?
Look for the label on the back or bottom, or check the manual. If it shows amps, multiply amps by 120 volts.
Results are estimates based on the official rates linked above. Confirm important figures with the issuing authority or a qualified adviser before you act on them.
Reviewed by ToolsUnlocked Team · Last updated