Electricity Cost Calculator
This electricity cost calculator shows you exactly how much an appliance costs to run each day, each month, and each year. Enter the appliance's rated power in watts, the average number of hours you use it per day, and your electricity rate in dollars per kWh. The default rate of $0.12/kWh reflects the approximate national average for US residential customers as published by the U.S. Energy Information Administration (EIA), though your actual rate will vary by state and utility. To find your specific rate, look at the energy charge line on your most recent utility bill. The formula multiplies power (in kW) by hours to get kWh, then multiplies by the rate. For example, a 1,500W space heater running 6 hours a day at $0.12/kWh costs $1.08 per day, $32.40 per month (30 days), and $388.80 per year. You can use these figures to compare the running cost of different appliances before purchasing, to budget for seasonal equipment like air conditioners or heaters, or to identify the biggest energy consumers in your home.
How electricity cost is calculated
The calculation converts wattage to kWh then applies your rate:
Daily kWh = Power (W) × Hours per day / 1,000
Daily cost ($) = Daily kWh × Rate ($/kWh)
Monthly cost ($) = Daily cost × Days per month
Annual cost ($) = Monthly cost × 12
Worked example: 1,500W space heater, 6 hours/day, $0.12/kWh, 30 days
- Daily kWh = 1,500 × 6 / 1,000 = 9.00 kWh
- Daily cost = 9.00 × $0.12 = $1.08
- Monthly kWh = 9.00 × 30 = 270.00 kWh
- Monthly cost = $1.08 × 30 = $32.40
- Annual cost = $32.40 × 12 = $388.80
Frequently asked questions
How do I find my electricity rate?
Your electricity rate (cost per kWh) appears on your utility bill, usually listed as the energy charge in cents per kWh. It may be a flat rate or a tiered rate that rises as you consume more. You can also look up average rates by state on the U.S. Energy Information Administration website at eia.gov. Rates typically range from around 10 cents per kWh in low-cost states to over 30 cents per kWh in high-cost states like Hawaii and California.
What is the average US electricity rate?
According to the U.S. Energy Information Administration (EIA), the national average residential electricity rate is approximately 12 cents per kWh, though this varies significantly by state and season. The EIA publishes monthly state-level averages in its Electric Power Monthly report. Your actual rate may differ based on your utility, local taxes, distribution charges, and any time-of-use pricing plan.
How can I reduce my electricity costs?
The most effective steps are to replace high-wattage appliances with energy-efficient alternatives (look for Energy Star certification), reduce usage hours, and unplug devices on standby. Large consumers like water heaters, air conditioners, clothes dryers, and electric ranges account for the majority of most household electricity bills. The U.S. Department of Energy estimates heating and cooling alone represents about 50% of home energy use.
What is standby power usage?
Standby power, sometimes called phantom load or vampire power, is the electricity drawn by a device when it is switched off but still plugged in. The U.S. Department of Energy estimates that standby power accounts for around 5-10% of residential electricity use. Common culprits include televisions, set-top boxes, game consoles, phone chargers, and microwave ovens with clocks. Using smart power strips or unplugging devices can eliminate this waste.
How do I read a utility bill?
A residential electricity bill typically shows: your billing period dates, meter readings (in kWh) at the start and end of the period, total kWh consumed, a breakdown of charges (energy charge, distribution charge, transmission charge, taxes, and fees), and the total amount due. The energy charge (cents per kWh) is the component this calculator uses. Other charges are fixed or semi-fixed and do not vary directly with consumption.
Sources
- U.S. Energy Information Administration, Electric Power Monthly: eia.gov/electricity/monthly.
- U.S. Department of Energy, Estimating Appliance and Home Electronic Energy Use: energy.gov.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology. General information only.