Electricity Cost Calculator
Calculate electricity cost for any appliance by wattage.
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How It Works
Calculates the cost to run an electrical device: Cost = Power (kW) × Hours × Rate ($/kWh). The kWh is the standard unit on your electricity bill.
Formula
Cost = kWh x RateQuick Reference
Common calculations — results you can verify instantly.
1500W heater, 8hr/day
1.5×8×$0.12
$1.44/day
TV 100W, 4hr/day
0.1×4×$0.12
$0.048/day
AC 3000W, 8hr/day
3×8×$0.12
$2.88/day
Tips & Shortcuts
US average electricity rate: ~$0.12/kWh. Hawaii is highest (~$0.34). Louisiana is lowest (~$0.09).
Phantom load: devices on standby still consume 1-10W. Unplug unused devices.
A refrigerator runs ~150W continuously = ~130 kWh/month = ~$16/month at $0.12.
Common Mistakes
Using watts directly without converting to kilowatts
Convert watts to kilowatts first (÷1000). 1500W = 1.5 kW. Cost = 1.5 × hours × rate.
Ignoring standby/idle power consumption
TVs, game consoles, and smart devices use power even when off. Annual standby cost can add up to $100+.
Frequently Asked Questions
A typical EV needs 30-40 kWh per 100 miles. At $0.12/kWh, that is $3.60-4.80 per 100 miles.
Heating and cooling (45%), water heater (18%), large appliances (15%), lighting (10%), electronics (12%).
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