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Electricity Cost Calculator

Calculate the cost to run any electrical appliance. Enter power, usage hours, and your electricity rate to estimate monthly and yearly energy costs.

How to Calculate Electricity Costs

Understanding Electricity Costs

Electricity is billed based on energy consumption measured in kilowatt-hours (kWh). One kWh represents the energy used by a 1,000-watt appliance running for one hour. Understanding this unit is the key to estimating how much any device costs to operate — from a small LED bulb to a central air conditioner.

Your electricity rate (measured in $/kWh) varies by location, provider, and time of use. The U.S. national average residential rate is approximately $0.16 per kWh as of 2024 (EIA), but rates can range from under $0.10 in states like Louisiana to over $0.30 in Hawaii and California.

The Electricity Cost Formula

Energy (kWh): Energy = (Power (W) × Time (h)) / 1000

Cost: Cost = Energy (kWh) × Rate ($/kWh)

Monthly Cost: Monthly Cost = Daily Energy × Days Per Month × Rate

U.S. average residential electricity rate ≈ $0.16/kWh (EIA 2024). Check your utility bill for your exact rate.

The formula is straightforward: convert wattage to kilowatts, multiply by hours of use, then multiply by your electricity rate. For monthly estimates, factor in how many days per month the appliance runs.

Worked Example

Scenario: A 1,500W space heater runs 8 hours per day, 30 days per month, at a rate of $0.16/kWh.

Daily Energy: (1500 W × 8 h) / 1000 = 12 kWh/day
Daily Cost: 12 kWh × $0.16 = $1.92/day
Monthly Energy: 12 kWh × 30 days = 360 kWh/month
Monthly Cost: 360 kWh × $0.16 = $57.60/month
Yearly Energy: 12 kWh × 365 days = 4,380 kWh/year
Yearly Cost: 4,380 kWh × $0.16 = $700.80/year

Practical Tips

Watch for phantom loads: Devices on standby (TVs, game consoles, chargers) can draw 1–10W continuously — costing $1–15/year each. Use smart power strips to eliminate standby drain.
Know your state's rate: Electricity rates vary dramatically by state. California and Hawaii residents often pay 2–3× the national average, while states like Washington, Louisiana, and North Dakota enjoy some of the lowest rates in the country.
Biggest energy hogs: Electric water heaters, HVAC systems, and electric dryers are typically the largest energy consumers in a home. A standard electric water heater alone can account for 300–500 kWh/month.
Time-of-use pricing: Many utilities charge less during off-peak hours (nights/weekends). Shifting laundry, dishwashing, or EV charging to off-peak times can save 10–30% on your bill.

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Frequently Asked Questions

How much does it cost to run a 1500W heater per hour?

At the U.S. average rate of $0.16/kWh, a 1500W heater costs approximately $0.24 per hour to run (1.5 kW × $0.16 = $0.24). Over an 8-hour day, that adds up to about $1.92, or $57.60 per month if used every day.

What is the average electricity rate in the US?

The average residential electricity rate in the U.S. is approximately $0.16 per kWh as of 2024, according to the U.S. Energy Information Administration (EIA). However, rates vary significantly by state — from around $0.10/kWh in states like Louisiana and North Dakota to over $0.30/kWh in Hawaii and $0.25–0.30/kWh in California.

How many kWh does a typical refrigerator use per month?

A modern energy-efficient refrigerator uses approximately 30–50 kWh per month, while older or larger models may consume 50–80 kWh. At $0.16/kWh, that translates to roughly $4.80–$8.00 per month for an efficient unit, or $8–$12.80 for an older one.

How can I find my exact electricity rate?

Check your monthly utility bill — the rate is usually listed in $/kWh and may be broken into supply, delivery, and surcharge components. You can also log into your utility provider's website or app, or call their customer service line. Note that some utilities use tiered or time-of-use rates, meaning the rate changes based on how much you use or when you use it.