Calculate Electricity Cost
This electricity cost calculator estimates how much it costs to run any appliance based on its wattage, usage hours, and your electricity rate.
Calculation Breakdown
How Electricity Cost Is Calculated
The electricity cost calculator uses this formula:
Cost = (Watts ÷ 1000) × Hours × Rate per kWh
Step-by-Step Example
Calculate the cost to run a 1500W space heater for 4 hours at $0.12/kWh:
- Convert watts to kilowatts: 1500W ÷ 1000 = 1.5 kW
- Calculate energy used: 1.5 kW × 4 hours = 6 kWh
- Calculate cost: 6 kWh × $0.12 = $0.72 per day
Monthly cost (30 days): $0.72 × 30 = $21.60
What Is a Kilowatt-Hour (kWh)?
A kilowatt-hour is the standard unit for measuring electricity consumption. It represents using 1000 watts of power for one hour. Your utility bill charges you based on total kWh consumed during the billing period.
Common Appliance Electricity Costs
Reference table showing typical wattages and estimated monthly costs at $0.12/kWh:
| Appliance | Typical Wattage | Monthly Cost* |
|---|---|---|
| LED Light Bulb (10 hrs/day) | 10W | $0.36 |
| Incandescent Bulb (10 hrs/day) | 60W | $2.16 |
| Laptop Computer (8 hrs/day) | 50W | $1.44 |
| Desktop Computer (8 hrs/day) | 200W | $5.76 |
| Gaming PC (4 hrs/day) | 500W | $7.20 |
| Refrigerator (24 hrs/day) | 150W avg | $12.96 |
| 55" LED TV (5 hrs/day) | 100W | $1.80 |
| Washing Machine (7 loads/week) | 500W | $1.80 |
| Electric Dryer (7 loads/week) | 3000W | $10.80 |
| Microwave (30 min/day) | 1000W | $1.80 |
| Space Heater (4 hrs/day) | 1500W | $21.60 |
| Window AC Unit (8 hrs/day) | 1200W | $34.56 |
| Central AC (6 hrs/day) | 3500W | $75.60 |
| Electric Water Heater | 4500W | $40-60 |
| EV Charger (Level 2, 3 hrs/day) | 7200W | $77.76 |
*Costs based on $0.12/kWh and typical daily usage. Actual costs vary by usage patterns and local rates.
Electricity Rates by State
Average residential electricity rates vary significantly across the US. Here are approximate rates for selected states:
Rates as of 2024. Check your utility bill for your actual rate.
Tips to Reduce Electricity Costs
Biggest Impact Changes
- Adjust your thermostat — Set AC to 78°F (26°C) in summer. Each degree lower adds 3-5% to cooling costs. In winter, set heat to 68°F when home, lower when away.
- Switch to LED bulbs — LEDs use 75-80% less energy than incandescent bulbs and last 25 times longer. A home switching 20 bulbs saves ~$150/year.
- Upgrade old appliances — ENERGY STAR refrigerators use 15% less energy. Old refrigerators (15+ years) can cost $100+ more per year to run.
Easy Daily Habits
- Unplug devices when not in use — TVs, game consoles, and chargers draw "vampire power" even when off. Use smart power strips to cut standby power.
- Wash clothes in cold water — 90% of washing machine energy goes to heating water. Cold water cleans effectively for most loads.
- Air dry when possible — Electric dryers cost $0.36-0.60 per load. Line drying or using a drying rack saves $50-100/year.
- Use ceiling fans — Fans use 10% of the energy of AC. They can make a room feel 4°F cooler, letting you raise the thermostat.
Time-of-Use Savings
If your utility offers time-of-use (TOU) pricing, run major appliances during off-peak hours (typically 9 PM - 7 AM). Off-peak rates can be 30-50% lower. Good candidates for off-peak scheduling:
- Dishwasher
- Washing machine and dryer
- Electric vehicle charging
- Pool pump
Frequently Asked Questions
How do I calculate the electricity cost of an appliance?
Multiply the appliance wattage by hours used, divide by 1000 to get kWh, then multiply by your electricity rate. Formula: Cost = (Watts ÷ 1000) × Hours × Rate per kWh. For example, a 1500W heater running 4 hours at $0.12/kWh costs (1500÷1000) × 4 × 0.12 = $0.72 per day.
What is a kWh and how is it calculated?
A kilowatt-hour (kWh) is a unit of energy equal to using 1000 watts for one hour. To calculate kWh, multiply the appliance wattage by hours of use, then divide by 1000. A 100W light bulb running for 10 hours uses 1 kWh (100 × 10 ÷ 1000 = 1).
What is the average electricity rate in the US?
The average US residential electricity rate is approximately $0.12-0.16 per kWh. However, rates vary significantly by state—from around $0.08/kWh in states like Louisiana to over $0.30/kWh in Hawaii. Check your utility bill for your exact rate.
How much does it cost to run a space heater all day?
A typical 1500W space heater running 24 hours at $0.12/kWh costs about $4.32 per day or $130 per month. Running it 8 hours daily costs approximately $1.44/day or $43/month. Space heaters are among the most expensive appliances to operate.
Does leaving appliances plugged in use electricity?
Yes, many electronics draw "standby power" (vampire load) even when turned off. TVs, game consoles, phone chargers, and computers can collectively cost $100-200 per year. Using smart power strips that cut power completely can eliminate this waste.
What appliances use the most electricity?
The biggest electricity consumers in most homes are: 1) Air conditioning/heating (40-50% of bills), 2) Water heaters (14-18%), 3) Refrigerators (4-8%), 4) Clothes dryers (4-6%), and 5) Lighting (4-6%). Reducing HVAC usage has the biggest impact on bills.
Is it cheaper to run appliances at night?
Only if your utility offers time-of-use (TOU) pricing. With TOU rates, electricity costs less during off-peak hours (typically 9 PM - 7 AM). Check if your utility offers TOU plans—savings can be 30-50% for running dishwashers, laundry, and EV charging at night.
How much electricity does a refrigerator use per month?
A modern refrigerator uses about 100-400 kWh per year, averaging 150W when running (but it cycles on/off). At $0.12/kWh, this costs roughly $12-48 per year or $1-4 per month. Older refrigerators can use 2-3 times more energy.
How do I find my electricity rate per kWh?
Check your electricity bill—look for "price per kWh" or "energy charge." Divide the total energy charges by total kWh used for an accurate rate. Some bills show tiered rates (higher rates after certain usage) or separate delivery charges to include.
What uses more electricity — AC or a space heater?
Central AC typically uses more total electricity (3000-5000W) but is more efficient at cooling large spaces. A 1500W space heater uses less power but only heats small areas. Per hour: AC costs $0.36-0.60, space heater costs $0.18. However, heat pumps are 2-3x more efficient than resistive heaters.
How can I reduce my electricity bill?
Top ways to cut electricity costs: 1) Set AC to 78°F (each degree lower adds 3-5% to cooling costs), 2) Switch to LED bulbs (75% less energy), 3) Unplug standby devices or use smart strips, 4) Wash clothes in cold water, 5) Air dry instead of using dryer, 6) Use ceiling fans before AC.
How much does it cost to charge an electric car?
Charging an EV costs roughly $0.03-0.05 per mile at average US rates. A typical EV with 60 kWh battery costs $7-10 for a full charge at home ($0.12/kWh). This equals about 200-250 miles of range. Public fast chargers cost 2-3x more.
Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are estimates and may vary based on actual conditions.
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Electricity Cost Calculator FAQ
How do I calculate the electricity cost of an appliance?
Multiply the appliance wattage by hours used, divide by 1000 to get kWh, then multiply by your electricity rate. Formula: Cost = (Watts ÷ 1000) × Hours × Rate per kWh. For example, a 1500W heater running 4 hours at $0.12/kWh costs (1500÷1000) × 4 × 0.12 = $0.72 per day.
What is a kWh and how is it calculated?
A kilowatt-hour (kWh) is a unit of energy equal to using 1000 watts for one hour. To calculate kWh, multiply the appliance wattage by hours of use, then divide by 1000. A 100W light bulb running for 10 hours uses 1 kWh (100 × 10 ÷ 1000 = 1).
What is the average electricity rate in the US?
The average US residential electricity rate is approximately $0.12-0.16 per kWh as of 2024. However, rates vary significantly by state—from around $0.08/kWh in states like Louisiana to over $0.30/kWh in Hawaii. Check your utility bill for your exact rate.
How much does it cost to run a space heater all day?
A typical 1500W space heater running 24 hours at $0.12/kWh costs about $4.32 per day or $130 per month. Running it 8 hours daily costs approximately $1.44/day or $43/month. Space heaters are among the most expensive appliances to operate.
Does leaving appliances plugged in use electricity?
Yes, many electronics draw 'standby power' (vampire load) even when turned off. TVs, game consoles, phone chargers, and computers can collectively cost $100-200 per year. Using smart power strips that cut power completely can eliminate this waste.
What appliances use the most electricity?
The biggest electricity consumers in most homes are: 1) Air conditioning/heating (40-50% of bills), 2) Water heaters (14-18%), 3) Refrigerators (4-8%), 4) Clothes dryers (4-6%), and 5) Lighting (4-6%). Reducing HVAC usage has the biggest impact on bills.
Is it cheaper to run appliances at night?
Only if your utility offers time-of-use (TOU) pricing. With TOU rates, electricity costs less during off-peak hours (typically 9 PM - 7 AM). Check if your utility offers TOU plans—savings can be 30-50% for running dishwashers, laundry, and EV charging at night.
How much electricity does a refrigerator use per month?
A modern refrigerator uses about 100-400 kWh per year, averaging 150W when running (but it cycles on/off). At $0.12/kWh, this costs roughly $12-48 per year or $1-4 per month. Older refrigerators can use 2-3 times more energy.
How do I find my electricity rate per kWh?
Check your electricity bill—look for 'price per kWh' or 'energy charge.' Divide the total energy charges by total kWh used for an accurate rate. Some bills show tiered rates (higher rates after certain usage) or separate delivery charges to include.
What uses more electricity - AC or a space heater?
Central AC typically uses more total electricity (3000-5000W) but is more efficient at cooling large spaces. A 1500W space heater uses less power but only heats small areas. Per hour: AC costs $0.36-0.60, space heater costs $0.18. However, heat pumps are 2-3x more efficient than resistive heaters.
How can I reduce my electricity bill?
Top ways to cut electricity costs: 1) Set AC to 78°F (each degree lower adds 3-5% to cooling costs), 2) Switch to LED bulbs (75% less energy), 3) Unplug standby devices or use smart strips, 4) Wash clothes in cold water, 5) Air dry instead of using dryer, 6) Use ceiling fans before AC.
How much does it cost to charge an electric car?
Charging an EV costs roughly $0.03-0.05 per mile at average US rates. A typical EV with 60 kWh battery costs $7-10 for a full charge at home ($0.12/kWh). This equals about 200-250 miles of range. Public fast chargers cost 2-3x more.