Electricity Cost Calculator
Find out exactly how much any appliance costs to run — per day, per month, and per year. Just enter the wattage, usage, and your electricity rate.
Calculate Electricity Cost
Result
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kWh per Day
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Daily Cost
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Monthly Cost (30 days)
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Yearly Cost
Formula
kWh per day = (Watts × Hours per day) ÷ 1000
Daily cost = kWh per day × Cost per kWh
Monthly cost = Daily cost × 30
Daily cost = kWh per day × Cost per kWh
Monthly cost = Daily cost × 30
Example Calculation
Running a 1,500W space heater for 8 hours per day at $0.13/kWh:
kWh/day = (1500 × 8) ÷ 1000 = 12 kWh/day
Daily cost = 12 × $0.13 = $1.56/day
Monthly cost = $1.56 × 30 = $46.80/month
Yearly cost = $1.56 × 365 = $569.40/year
Daily cost = 12 × $0.13 = $1.56/day
Monthly cost = $1.56 × 30 = $46.80/month
Yearly cost = $1.56 × 365 = $569.40/year
Common Appliance Wattages
- Electric kettle: 1,200–3,000W
- Microwave: 600–1,200W
- Air conditioner (window unit): 900–1,440W
- Refrigerator: 100–400W (varies by size)
- LED light bulb: 8–15W
- Desktop PC: 200–800W depending on GPU
- Electric vehicle charger (Level 2): 7,200–11,500W
Frequently Asked Questions
How do I calculate electricity cost from watts?
Convert to kWh first: kWh/day = (Watts × Hours) ÷ 1000. Then multiply by your electricity rate: Cost = kWh × price per kWh. Check your electricity bill for your rate.
What is the average electricity rate in the US?
The US average is around $0.13–$0.17 per kWh depending on your state. Hawaii is highest (~$0.38/kWh) and Louisiana is among the lowest (~$0.09/kWh). Check your utility bill for your exact rate.
How much does it cost to run a 1500W heater for 8 hours?
At $0.13/kWh: (1500 × 8) ÷ 1000 × $0.13 = $1.56 per day, or about $46.80 per month. At $0.20/kWh it would be $2.40/day or $72/month.