Electricity Cost Calculator
Estimate how much your appliances cost to run by the day, week, month, or year based on their wattage, usage hours, and your local electricity rate.
Find this on your utility bill (US average ~$0.17)
Month Cost
$130
per month
Month Energy
764
kWh
Annual Cost
$1,557
per year
Daily Energy
25.1
kWh/day
Refrigerator
150W · 24 hrs/day · 109.6 kWh
$19
per month
Central AC
3500W · 6 hrs/day · 639.2 kWh
$109
per month
LED TV
100W · 5 hrs/day · 15.2 kWh
$3
per month
What is an Electricity Cost Calculator?
An electricity cost calculator is a tool that estimates how much it costs to run your electrical appliances and devices over any time period. By combining each appliance's power draw (in watts), how many hours you use it, and your local electricity rate (the price per kilowatt-hour), it turns confusing utility bills into clear, itemized numbers you can actually act on.
Most people have no idea which devices drive their electric bill. Is it the air conditioner, the old refrigerator, the gaming PC, or all those phantom standby loads? This calculator answers that question directly, showing you the daily, weekly, monthly, and yearly cost of each appliance side by side so you can see exactly where your money goes.
Whether you want to budget more accurately, decide if a high-efficiency upgrade is worth it, size a solar system, or simply cut waste, understanding your electricity costs at the appliance level is the first step. This calculator makes that breakdown instant and easy to understand.
How to Use the Electricity Cost Calculator
Add Your Appliances
Use the quick preset menu to load typical wattages for common devices, or type in your own appliance name.
Enter Wattage & Hours
Set each appliance's watts, how many hours per day you use it, and the quantity if you have more than one.
Set Your Rate
Enter your electricity rate per kWh from your utility bill. The US average is around 17 cents per kWh.
Review the Breakdown
Choose a billing period and see the cost and energy use for each appliance, plus your projected annual cost.
The Electricity Cost Formula Explained
Electricity cost is calculated by converting watts to kilowatt-hours, then multiplying by your rate:
1. Daily Energy Use (kWh)
kWh/day = (Watts × Hours per day × Quantity) ÷ 1,000
2. Energy for the Period
Period kWh = kWh/day × Days in period
3. Cost
Cost = Period kWh × Rate per kWh
Worked example: A 3,500-watt central AC running 6 hours a day uses (3,500 × 6) ÷ 1,000 = 21 kWh per day. Over a 30.44-day month that is 639 kWh. At $0.17 per kWh, the monthly cost is 639 × 0.17 = ~$108.65.
Example Calculations
Tips to Lower Your Electricity Costs
Target high-wattage devices
Focus on heating, cooling, and water heating first — they usually account for the largest share of your bill.
Switch to LED lighting
LEDs use up to 90% less energy than incandescent bulbs and last far longer, with quick payback.
Use a programmable thermostat
Automatically setting back temperatures while you sleep or are away can cut heating and cooling costs significantly.
Beware phantom loads
Electronics on standby still draw power. Smart power strips cut this hidden waste from TVs, consoles, and chargers.
Shift to off-peak hours
If you have time-of-use pricing, run dishwashers, laundry, and EV charging during cheaper off-peak windows.
Upgrade to ENERGY STAR
When replacing major appliances, certified models use substantially less electricity for the same performance.
Understanding Watts, kWh, and Your Energy Bill
Your electricity bill is built on a simple idea: you pay for energy, and energy is power used over time. Power is measured in watts (W) or kilowatts (kW, where 1 kW = 1,000 W). Energy is measured in kilowatt-hours (kWh) — using 1 kW of power for 1 hour equals 1 kWh. Utilities bill you per kWh, so both how powerful a device is and how long it runs matter equally.
This is why a low-wattage device that runs constantly can cost more than a high-wattage device used briefly. A 150-watt refrigerator running 24/7 uses more energy over a month than a 1,500-watt hair dryer used 10 minutes a day. Looking at wattage alone is misleading — runtime is just as important, which is exactly what this calculator captures.
| Appliance | Typical Wattage | Est. Monthly Cost* |
|---|---|---|
| Central Air Conditioner | 3,500 W | ~$107 (6 hr/day) |
| Electric Water Heater | 4,000 W | ~$61 (3 hr/day) |
| Refrigerator | 150 W | ~$19 (24 hr/day) |
| Clothes Dryer | 3,000 W | ~$31 (1 hr/day) |
| LED TV | 100 W | ~$2.55 (5 hr/day) |
| LED Light Bulb | 10 W | ~$0.26 (5 hr/day) |
*Estimated at $0.17 per kWh. Actual costs vary by rate and usage.
For official electricity rate data and energy-saving guidance, see the U.S. Energy Information Administration (EIA) and the ENERGY STAR program for appliance efficiency ratings.
Frequently Asked Questions
How do I calculate the cost of running an appliance?
Multiply the appliance wattage by the hours used per day, then divide by 1,000 to get kilowatt-hours (kWh) per day. Multiply by your electricity rate (cost per kWh) to get the daily cost, then by the number of days for weekly, monthly, or yearly figures. This calculator does all of this automatically for every appliance you add.
What is a kilowatt-hour (kWh)?
A kilowatt-hour is the standard unit of energy your utility bills you for. It equals 1,000 watts of power used for one hour. For example, a 100-watt bulb running for 10 hours uses 1 kWh. Your electricity rate is the price you pay per kWh, typically shown on your utility bill.
What is the average electricity rate?
The U.S. average residential electricity rate is around 16 to 17 cents per kWh as of 2024, though it varies widely by state — from about 11 cents in some areas to over 40 cents in Hawaii. Check your utility bill for your exact rate and enter it for the most accurate cost estimate.
How can I find an appliance's wattage?
Look for a label or nameplate on the appliance, usually on the back or bottom, listing watts (W) or amps (A) and volts (V). If only amps are listed, multiply amps × volts to get watts. You can also use a plug-in energy monitor for an exact reading, or use the typical values built into this calculator.
Which appliances use the most electricity?
Heating and cooling typically dominate home energy use — central air conditioning, electric heating, and water heaters are the biggest consumers. Clothes dryers, electric ovens, and refrigerators (because they run constantly) also use significant electricity. Lighting and electronics usually account for a smaller share.
How can I reduce my electricity bill?
Focus on your biggest energy users first. Adjust your thermostat, use a programmable or smart thermostat, switch to LED lighting, run major appliances during off-peak hours if you have time-of-use rates, unplug idle electronics, and upgrade to ENERGY STAR appliances. Even small changes to high-wattage, long-runtime devices add up quickly.