How this electricity cost calculator works
Electricity is billed in kilowatt-hours (kWh). To find a device's use, multiply its power in watts by the hours it runs, then divide by 1,000. Multiply the kWh by your rate per kWh to get the cost. A 100-watt TV running 4 hours a day uses 0.4 kWh a day; at $0.17 per kWh that's about $2 a month.
Add each device with its wattage, hours per day and quantity. The calculator totals daily, monthly and yearly energy and cost and shows which devices cost the most.
Finding wattage and your rate
Wattage is usually printed on a label on the device or in its manual. If it lists amps and volts instead, multiply them to get watts. Your electricity rate is on your utility bill, in dollars per kWh — use the total cost divided by total kWh if your bill has several charges.
Ways to lower your electricity bill
- Heating and cooling dominate. Air conditioners, space heaters and electric dryers use far more than lighting or electronics.
- Switch to LED bulbs. They use about 75–80% less energy than incandescent bulbs.
- Beware standby power. Devices left plugged in still draw a few watts; a power strip makes them easy to switch off.
- Ask about time-of-use rates. Running big appliances off-peak can cost noticeably less with some utilities.
Frequently asked questions
How do I calculate electricity cost?
Cost = watts × hours used ÷ 1,000 × your rate per kWh. This calculator does the math for each device and adds them up for daily, monthly and yearly totals.
What is a kWh?
A kilowatt-hour is the energy used by a 1,000-watt device running for one hour. It's the unit your utility bills you in.
What is the average electricity rate?
The average US residential rate is roughly $0.15–$0.20 per kWh, but it ranges widely by state and utility. Check your own bill for the exact number.
How do I handle appliances that cycle on and off?
Refrigerators, air conditioners and heaters only run part of the time. Use their average draw — the preset for a refrigerator already reflects this — or reduce the hours per day to match how long they actually run.
Are the preset wattages exact?
No. They are typical values for common devices. Use the wattage printed on your own devices for a more accurate result.
This calculator is for general informational purposes only. Actual usage and cost depend on your devices, habits and utility rates.