Energy Consumption Calculator — Electricity Cost Estimator
Calculate electricity consumption and cost for any appliance. Enter wattage, usage hours, and electricity rate to estimate daily and monthly costs. Includes a comprehensive reference table of common household appliance energy usage. See also our Energy Converter and Power Converter.
Heating
| Appliance | Energy Use | Cost (at $0.13/kWh) |
|---|---|---|
| Portable heater (1500W) | 1.5 kWh/hour | $0.20/hour |
| Baseboard heater (6ft, 250W/ft) | 1.5 kWh/hour | $0.20/hour |
| Heat pump heat strips | 10 kWh/hour | $1.30/hour |
| Electric furnace | 10.5 kWh/hour | $1.37/hour |
Air Conditioning/Cooling
| Appliance | Energy Use | Cost (at $0.13/kWh) |
|---|---|---|
| Window/wall AC (8kBtu, 12 EER) | 0.73 kWh/hour | $0.09/hour |
| Window/wall AC (18kBtu, 240V) | 1.8 kWh/hour | $0.23/hour |
| Central AC (3 ton, 12 SEER) | 3.0 kWh/hour | $0.39/hour |
| Whole house fan | 0.2-0.4 kWh/hour | $0.03-$0.05/hour |
| Ceiling fan | 0.025-0.075 kWh/hour | <$0.01/hour |
Water Heating
| Appliance | Energy Use | Cost (at $0.13/kWh) |
|---|---|---|
| Electric water heater | 380-500 kWh/month | $49-$65/month |
| Heat pump water heater (50-75 gal) | 77 kWh/month | $10/month |
| Instantaneous (240V, 50A) | 12 kWh/hour | $1.56/hour |
Kitchen
| Appliance | Energy Use | Cost (at $0.13/kWh) |
|---|---|---|
| Oven | 2.3 kWh/hour | $0.30/hour |
| Oven surface/stovetop | 1-1.5 kWh/hour | $0.13-$0.20/hour |
| Microwave oven | 0.12 kWh/5 min | $0.02/5 min |
| Dishwasher (normal cycle) | 1-2.17 kWh/load | $0.13-$0.28/load |
| Coffee maker | 0.12 kWh/brew | $0.02/brew |
| Toaster (2 slices) | 0.04 kWh/use | <$0.01/use |
Refrigerator/Freezer
| Appliance | Energy Use | Cost (at $0.13/kWh) |
|---|---|---|
| ENERGY STAR Refrigerator (17 cu ft) | 35 kWh/month | $4.55/month |
| ENERGY STAR Refrigerator (21 cu ft, side-by-side) | 51 kWh/month | $6.63/month |
| Older Refrigerator (15 cu ft, 1996) | 150 kWh/month | $19.50/month |
| Freezer (manual defrost, 15 cu ft) | 90 kWh/month | $11.70/month |
Laundry
| Appliance | Energy Use | Cost (at $0.13/kWh) |
|---|---|---|
| Clothes washer (warm wash, cold rinse) | 2.3 kWh/load | $0.30/load |
| Clothes dryer | 2.5-4.0 kWh/load | $0.33-$0.52/load |
| Iron | 1.0 kWh/hour | $0.13/hour |
Lighting
| Appliance | Energy Use | Cost (at $0.13/kWh) |
|---|---|---|
| LED bulb (10W, replaces 60W) | 0.01 kWh/hour | $0.001/hour |
| CFL bulb (13W, replaces 60W) | 0.013 kWh/hour | $0.002/hour |
| Incandescent bulb (60W) | 0.06 kWh/hour | $0.008/hour |
| Incandescent bulb (100W) | 0.1 kWh/hour | $0.013/hour |
Electronics
| Appliance | Energy Use | Cost (at $0.13/kWh) |
|---|---|---|
| Desktop computer | 0.15-0.3 kWh/hour | $0.02-$0.04/hour |
| Laptop | 0.02-0.05 kWh/hour | <$0.01/hour |
| TV (LED, 50 inch) | 0.07 kWh/hour | $0.01/hour |
| Gaming console | 0.1-0.2 kWh/hour | $0.01-$0.03/hour |
Formula
Energy (kWh) = Wattage (W) × Hours / 1000
Cost = Energy (kWh) × Rate ($/kWh)
Monthly Cost = Daily Cost × 30
Example: 1500W heater × 5 hours = 7.5 kWh
Cost = 7.5 × $0.13 = $0.975/day = $29.25/monthWorked Examples
Example 1: Monthly Cost of Running a Window AC Unit
Given: 1,200W window AC, runs 8 hours/day, electricity rate = $0.15/kWh
Step 1: Daily energy = 1,200W × 8 hrs ÷ 1,000 = 9.6 kWh/day
Step 2: Daily cost = 9.6 kWh × $0.15 = $1.44/day
Step 3: Monthly cost = $1.44 × 30 = $43.20/month
Tip: A newer inverter AC with the same BTU rating may use 30-50% less power.
Example 2: Comparing LED vs Incandescent Lighting (10 bulbs)
Given: 10 bulbs running 6 hours/day, rate = $0.13/kWh
Incandescent (60W each): 10 × 60W × 6 hrs ÷ 1,000 = 3.6 kWh/day = $0.468/day = $14.04/month
LED equivalent (10W each): 10 × 10W × 6 hrs ÷ 1,000 = 0.6 kWh/day = $0.078/day = $2.34/month
Savings: $14.04 − $2.34 = $11.70/month saved ($140.40/year)
Example 3: Running Cost of an Electric Space Heater
Given: 1,500W heater, runs 10 hours/day for winter (4 months), rate = $0.16/kWh
Step 1: Daily energy = 1,500W × 10 hrs ÷ 1,000 = 15 kWh/day
Step 2: Daily cost = 15 kWh × $0.16 = $2.40/day
Step 3: Monthly cost = $2.40 × 30 = $72.00/month
Step 4: Winter season (4 months) = $72.00 × 4 = $288.00 total
Household Appliance Wattage Reference Table
Typical wattage and estimated monthly energy consumption for common household appliances (assuming average daily usage).
| Appliance | Typical Watts | Avg Daily Use | Monthly kWh |
|---|---|---|---|
| Refrigerator (modern) | 100-400 | 24 hrs (cycling) | 30-50 |
| Central Air Conditioner | 3,000-5,000 | 6-8 hrs | 540-1,200 |
| Window AC Unit (10,000 BTU) | 1,000-1,500 | 8 hrs | 240-360 |
| Electric Water Heater | 4,000-5,500 | 3 hrs | 360-495 |
| Clothes Dryer | 2,000-5,000 | 1 hr (3×/wk) | 26-65 |
| Washing Machine | 350-500 | 1 hr (3×/wk) | 5-7 |
| Dishwasher | 1,200-2,400 | 1 hr | 36-72 |
| Electric Oven/Range | 2,000-5,000 | 1 hr | 60-150 |
| Microwave Oven | 600-1,200 | 15 min | 5-9 |
| Toaster | 800-1,500 | 5 min | 2-4 |
| Coffee Maker | 600-1,200 | 10 min | 3-6 |
| LED TV (50") | 60-100 | 5 hrs | 9-15 |
| Desktop Computer | 150-350 | 4 hrs | 18-42 |
| Laptop Computer | 30-70 | 5 hrs | 5-11 |
| Gaming Console | 100-200 | 3 hrs | 9-18 |
| Wi-Fi Router | 5-20 | 24 hrs | 4-14 |
| LED Bulb (60W equiv) | 8-12 | 6 hrs | 1.4-2.2 |
| Incandescent Bulb (60W) | 60 | 6 hrs | 10.8 |
| Ceiling Fan | 25-75 | 8 hrs | 6-18 |
| Space Heater | 750-1,500 | 8 hrs | 180-360 |
| Hair Dryer | 1,000-1,800 | 10 min | 5-9 |
| Iron | 1,000-1,800 | 30 min (2×/wk) | 4-7 |
| Vacuum Cleaner | 500-1,400 | 30 min (2×/wk) | 2-6 |
| Electric Vehicle Charger (Level 2) | 3,300-7,700 | 3-4 hrs | 300-920 |
FAQ
How to calculate electricity cost?
Multiply wattage by hours of use, divide by 1000 to get kWh, then multiply by your electricity rate. Example: 100W × 10 hours = 1 kWh × $0.13 = $0.13/day.
What uses the most electricity in a home?
Heating/cooling (46%), water heating (14%), appliances (13%), lighting (9%), and electronics (4%) are the biggest consumers in a typical US home.
How much does it cost to run a 1500W heater?
At $0.13/kWh: 1500W × 1 hour = 1.5 kWh = $0.195/hour. Running 8 hours/day = $1.56/day = $46.80/month.
What is the difference between peak and off-peak electricity rates?
Many utilities charge higher rates during peak demand hours (typically 2-7 PM on weekdays) and lower rates during off-peak hours (nights, weekends). Peak rates can be 2-3× higher. For example, if your off-peak rate is $0.08/kWh, peak might be $0.20-$0.35/kWh. Running high-wattage appliances (dryers, dishwashers, EV chargers) during off-peak hours can significantly reduce your bill.
What is phantom/standby power and how much does it cost?
Phantom power (also called vampire draw or standby power) is the electricity consumed by devices when they are turned off but still plugged in. TVs, game consoles, chargers, and computers in sleep mode all draw 1-10W continuously. The average US home wastes $100-$200/year on phantom loads. Use power strips to disconnect devices completely, or look for ENERGY STAR devices with low standby consumption (<0.5W).
How do I calculate solar panel offset for my electricity usage?
First find your monthly kWh usage from your electricity bill. Then divide by average sun hours per day (4-6 hours depending on location) and by 30 days. For example: 900 kWh/month ÷ 30 days ÷ 5 sun hours = 6 kW system needed. Each 400W panel produces about 1.6-2.0 kWh/day, so you would need approximately 15-19 panels to offset 900 kWh/month.
How does electricity rate vary by state?
US electricity rates vary significantly: Hawaii ($0.43/kWh), Connecticut ($0.29/kWh), California ($0.27/kWh), and New York ($0.23/kWh) are the highest. Louisiana ($0.10/kWh), Oklahoma ($0.10/kWh), and Wyoming ($0.11/kWh) are among the cheapest. The national average is approximately $0.16/kWh. Always use your actual rate from your utility bill for accurate calculations.
What is a kilowatt-hour (kWh)?
A kilowatt-hour is a unit of energy equal to using 1,000 watts for one hour (or 100 watts for 10 hours, etc.). It is how your utility company measures and bills your electricity consumption. One kWh can power a 100W light bulb for 10 hours, run a laptop for ~20 hours, or dry one load of laundry.
Energy Saving Tips
Switch to LED lighting: LED bulbs use 75-80% less electricity than incandescent and last 15-25× longer. Replacing 20 incandescent bulbs saves ~$150/year.
Set thermostat strategically: Each degree you raise AC (or lower heating) saves 3-5% on that portion of your bill. Use a programmable thermostat to adjust when you're away or sleeping.
Unplug phantom loads: Use smart power strips or unplug chargers, gaming consoles, and rarely used devices. This can save $100-$200/year.
Run appliances during off-peak hours: If your utility offers time-of-use rates, run dishwashers, dryers, and EV chargers at night for lower rates.
Upgrade to ENERGY STAR appliances: An ENERGY STAR refrigerator uses 9-10% less energy than standard models. A heat pump water heater uses 60-70% less than a conventional electric water heater.
Use cold water for laundry: About 90% of a washing machine's energy goes to heating water. Washing in cold water saves $60-$100/year with no impact on cleaning for most loads.
Seal air leaks and insulate: Drafty windows and poor insulation can increase heating/cooling costs by 20-30%. Weather-stripping and caulking are inexpensive fixes with big returns.
Use ceiling fans wisely: Fans cost only $0.01-$0.02/hour to run and can make a room feel 4-6°F cooler, allowing you to raise your AC thermostat and save significant cooling costs.
Objective of Measurement:
Measurement is the most important aspect of our life. We use measurement in science, engineering, business trading, personal life, education, and more other fields.