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Electricity Cost

Calculate the energy cost of any electrical appliance. Pick from 20 common appliance presets or enter custom wattage, usage hours, and electricity rate.

✓ Tested formula & cited sources Checked against independent sources · Oct 17, 2026 Private: runs in your browser

Pick a common appliance to auto-fill wattage

US average is ~$0.14/kWh

e.g., 10 LED bulbs

Results

Energy Cost (Month)

$25.20

Energy Used
180 kWh
Daily Usage
6 kWh
Cost Per Day
$0.84
Projected Monthly Cost
$25.20
Projected Yearly Cost
$306.60
Appliance
Custom Appliance
Comparison
Roughly equivalent to running a Space Heater for 4 hrs/day

The formula

Cost = (Watts × Hours/Day × Days) / 1000 × $/kWh × Quantity

W × h
Wattage & Usage
d
Number of Days
¢
Cost per kWh

Worked example — Appliance Wattage 1500, Hours Used Per Day 4, Electricity Rate ($/kWh) 0.14, Number of Appliances 1

Energy Cost (Month) = $25.20

Full explanation ↓

How Electricity Cost Works

Cost = (Watts × Hours/Day × Days) / 1000 × $/kWh × Quantity

Calculate the energy cost of any electrical appliance. First find kilowatt-hours (kWh), then multiply by your electricity rate.

W × h
Wattage & Usage — Power rating in Watts multiplied by hours of use per day. The foundation of energy consumption calculation.
d
Number of Days — Billing period or time span to calculate over.
¢
Cost per kWh — Your electricity rate in cents per kilowatt-hour. Found on your electric bill.
Electricity cost calculation: appliance wattage is converted to kilowatt-hours, then multiplied by the electricity rate.

Understanding the Result

Electricity is billed per kilowatt-hour (kWh), which represents 1,000 watts used for one hour. This calculator converts appliance wattage to kilowatt-hours, multiplies by your local electricity rate, and projects costs over daily, monthly, and yearly periods. Understanding appliance energy costs helps you identify energy-saving opportunities and manage your electric bill. Practical example: a gaming PC drawing 500W used for 6 hours per day. Daily consumption: (500 × 6) / 1000 = 3 kWh.

At $0.14/kWh, daily cost = $0.42, monthly cost (30 days) = $12.60, yearly cost = $153.30. Compare with an LED TV (120W) used 6 hours: 0.72 kWh/day, $0.10/day, $3.02/month, $36.79/year. The gaming PC costs over 4 times more to run. Edge cases: for appliances with variable power draw, such as refrigerators and air conditioners that cycle on and off, the nameplate wattage overestimates actual consumption — a refrigerator rated at 700W typically runs only about 30% of the time, averaging 210W.

Use a plug-in power meter (like a Kill-A-Watt) for accurate measurements. For electric vehicle charging at Level 2 (7,000W for 4 hours), consumption is 28 kWh/day, costing $3.92/day, $117.60/month, $1,430.80/year. Time-of-use billing can significantly affect costs — charging overnight at off-peak rates (potentially $0.08/kWh) versus peak rates ($0.30/kWh) can cut EV charging costs by 70%. For standby power (vampire power), devices like cable boxes, game consoles, and phone chargers draw 1-10W continuously — 10 such devices at 5W each, 24/7, use 1.2 kWh a day, which costs about $5/month at average rates, or $61/year in wasted energy.

How to Use

  1. Select an appliance from the Quick Select list to auto-fill wattage, or enter a custom value.
  2. Enter the average hours of use per day.
  3. Choose a period (Day, Week, Month, or Year) or use the default 30-day calculation.
  4. Enter your electricity rate in $/kWh (US average is ~$0.14).
  5. Set the number of identical appliances (e.g., 10 LED bulbs).

Quick Reference

1 kWh at $0.14/kWh (US avg)$0.14
10 kWh$1.40
20 kWh$2.80
50 kWh$7.00
100 kWh$14.00
150 kWh$21.00
200 kWh$28.00
500 kWh$70.00
1,000 kWh$140.00

Frequently Asked Questions

How much does 1 kWh cost, or any specific amount of kWh?
Cost = kWh used x your rate per kWh — no wattage or hours needed if you already know your kWh usage (e.g., from a bill or smart meter). At the US average rate of $0.14/kWh: 0.5 kWh = $0.07, 1 kWh = $0.14, 1.5 kWh = $0.21, 1.8 kWh = $0.25, 2 kWh = $0.28. See the quick reference table above for larger amounts (10-1,000 kWh). To use this calculator for a known kWh amount directly, set Appliance Wattage to 1000 and Hours Used Per Day to your kWh figure (since 1000W x 1h = 1 kWh) — or just multiply your kWh by your rate by hand, which is exactly what the calculator does internally.
How do I calculate the cost of running X watts for an hour?
Cost per hour = (Watts / 1000) x your rate per kWh. For example, a 1,500W space heater running for one hour costs 1.5 kWh x $0.14 = $0.21 at the US average rate. For "watts per hour" style questions where you know the wattage and want a running cost, enter the wattage above with Hours Used Per Day set to 1 and Calculate For set to Day — the Cost Per Day result is your hourly cost.
What is a kilowatt-hour (kWh)?
A kilowatt-hour is a unit of energy equal to using 1,000 watts for one hour. If a 100W light bulb runs for 10 hours, it uses 1 kWh. Your electric bill charges you per kWh consumed.
What is the average US electricity rate?
As of recent data, the US average residential electricity rate is approximately $0.14 per kWh. Rates vary significantly by state — from under $0.10 in some states to over $0.30 in others (e.g., Hawaii, California).
How can I reduce my electricity bill?
Replace incandescent bulbs with LEDs, unplug devices when not in use, use smart power strips, run major appliances during off-peak hours, maintain HVAC systems, improve home insulation, and consider energy-efficient appliances (look for ENERGY STAR ratings).

Sources

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Cite this calculator

TheCalcUniverse. "Electricity Cost Calculator — kWh to Dollars, Any Appliance." TheCalcUniverse, 2026, https://thecalcuniverse.com/engineering/electricity-cost-calculator/. Accessed October 25, 2026.

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