The average American household spends $137 per month on electricity, but most people have no idea which appliances are driving that bill. A single space heater running 8 hours a day costs about $45/month. A gaming PC left on 24/7 costs $15-$30/month. An old refrigerator can cost twice as much as an Energy Star model. This calculator converts watts, hours of use, and your local electricity rate into monthly and annual costs for any appliance, so you can identify the biggest energy drains in your home and make informed decisions about upgrades and usage habits.
Electricity Cost Calculator
Common Appliance Presets
How to Use This Calculator
- Enter the appliance wattage — check the label on the device or look up typical wattage for your appliance type
- Set the hours of daily use — be realistic about standby power for devices that draw current even when 'off'
- Enter your electricity rate in cents per kilowatt-hour — check your latest utility bill or use the national average of $0.16/kWh
- View the daily, monthly, and annual operating cost for that appliance
- Compare multiple appliances to find the biggest energy consumers in your home
How the Electricity Cost Calculator Works
This calculator converts appliance wattage and usage hours into kilowatt-hours, then multiplies by your electricity rate.
- kWh = Watts × Hours ÷ 1,000 (the unit your utility charges)
- Monthly = daily cost × 30 days
- Add multiple appliances to see your total running cost
- Check your utility bill for your exact $/kWh rate
Tips & Considerations
- Standby power ('vampire draw') from devices that are off but plugged in costs the average home $100-$200 per year. Smart power strips eliminate this.
- LED bulbs use 75% less electricity than incandescent bulbs. Replacing ten 60W bulbs with 10W LEDs saves about $100/year.
- Electricity rates vary from $0.08/kWh in Louisiana to $0.35/kWh in Hawaii. Your local rate dramatically changes whether efficiency upgrades make financial sense.
- Time-of-use rate plans charge more during peak hours (2-7pm typically) and less overnight. Running dishwashers and laundry after 9pm can save 30-50% on those cycles.
Frequently Asked Questions
How do you calculate electricity cost?
Multiply wattage by hours of use, divide by 1,000 to get kWh, then multiply by your electricity rate. Example: 1,500W space heater × 8 hours ÷ 1,000 = 12 kWh × $0.15 = $1.80/day.
How much does it cost to run an air conditioner?
A window AC (1,200W) running 8 hours/day costs about $1.44/day or $43/month. Central AC (3,500W) for 8 hours costs $4.20/day or $126/month at $0.15/kWh.
What is a kilowatt-hour (kWh)?
A kWh equals 1,000 watts used for one hour. It is the standard billing unit for electricity. A 100W bulb running 10 hours or a 1,000W microwave running 1 hour both use 1 kWh.
What is the average electricity rate?
The US average is about $0.15/kWh but varies by state from ~$0.10 (Louisiana) to ~$0.35 (Hawaii). Check your utility bill for the exact rate, which may include tiered pricing.
What appliances use the most electricity?
HVAC systems, water heaters, clothes dryers, and ovens draw the most watts. However, always-on devices like refrigerators and electronics on standby add up significantly over time.
How can I reduce my electricity bill?
Switch to LED bulbs, use a programmable thermostat, run heavy appliances during off-peak hours, unplug vampire loads, air-seal your home, and consider Energy Star rated appliances when replacing old ones.