Electricity Calculator
Calculate electricity costs and energy usage for appliances
How to Use This Electricity Calculator
- Select calculation mode: custom device wattage or common appliances
- Enter device wattage (check the label or manual for this number)
- Specify hours of use per day and days per month
- Enter your electricity rate (check your bill - US average is $0.16/kWh in 2026)
- Click calculate to see daily, monthly, and yearly costs
Example: A 1500W space heater running 4 hours daily at $0.16/kWh costs $0.96/day, $28.80/month, or $345/year. That single heater can add $30+ to winter electric bills.
Tip: Find your actual kWh rate on your electric bill - it varies from $0.10 in cheap states to $0.35+ in Hawaii and California.
Why Use a Electricity Calculator?
Understanding electricity costs helps identify energy hogs, reduce bills, and make informed appliance purchasing decisions.
- Calculate the true cost of running space heaters or window AC units
- Compare energy costs when shopping for new appliances
- Identify which devices are driving up your electric bill
- Estimate cost savings from upgrading to energy-efficient models
- Budget for electricity costs when working from home
- Evaluate solar panel or battery storage payback periods
Understanding Your Results
Electricity is measured in kilowatt-hours (kWh). One kWh is using 1,000 watts for one hour.
| Result | Meaning | Action |
|---|---|---|
| Under $5/month | Low impact | Minor devices like phone chargers and LED lights |
| $5-20/month | Moderate impact | Computers, TVs, and medium-use appliances |
| $20-50/month | Significant cost | Consider usage reduction or efficiency upgrades |
| Over $50/month | Major expense | Evaluate necessity or look for Energy Star alternatives |
Meaning: Low impact
Action: Minor devices like phone chargers and LED lights
Meaning: Moderate impact
Action: Computers, TVs, and medium-use appliances
Meaning: Significant cost
Action: Consider usage reduction or efficiency upgrades
Meaning: Major expense
Action: Evaluate necessity or look for Energy Star alternatives
Note: Standby power ('vampire load') from devices in sleep mode can account for 5-10% of household electricity use.
About Electricity Calculator
Formula
Cost = (Watts x Hours x Days x kWh Rate) / 1000 Divide watts by 1000 to get kilowatts, multiply by hours of use and your utility rate per kWh.
Current Standards: Average US electricity rate is approximately $0.16/kWh (2026), ranging from $0.10 in Louisiana to $0.45 in Hawaii. Commercial rates average $0.13/kWh.
Frequently Asked Questions
What uses the most electricity in a typical home?
Air conditioning and heating: 40-50% of bills. Water heater: 15-20%. Washer/dryer: 10-15%. Refrigerator: 5-10%. Electronics and lighting: 10-15%. A central AC running on a hot day can use 3-5 kW continuously - at $0.16/kWh, that's $0.48-0.80 per hour. Running AC 8 hours daily can cost $120-190/month.
Do phone chargers use electricity when not charging?
Yes, but minimal - about 0.1-0.5 watts in standby. At $0.16/kWh, leaving a charger plugged in costs roughly $0.50-1.00 per year. The bigger 'vampire loads' are cable boxes ($15-30/year), game consoles ($10-25/year), and computers in sleep mode ($10-25/year). Unplugging everything unnecessary could save $50-100 annually.
How much does it cost to run a space heater?
Most space heaters are 1,500W. Running one 8 hours daily at $0.16/kWh costs $57.60/month. For comparison, using central gas heat for the same room might cost $20-30/month in fuel. Space heaters are inefficient for whole-home heating but can save money when heating just one room while keeping the rest of the house cooler.
Are newer appliances really more efficient?
Dramatically so. A 2026 refrigerator uses about 400 kWh/year ($64); a 2006 model uses 700 kWh/year ($112); a 1990 model uses 1,200 kWh/year ($192). LED bulbs use 75% less energy than incandescent. Modern AC units (SEER 20+) use half the electricity of 15-year-old units (SEER 10). Efficiency improvements often pay for themselves in 2-5 years.
How can I find an appliance's wattage?
Check the label on the device (usually on the back or bottom), the manual, or manufacturer's website. Wattage might be listed directly or as amps and volts (Watts = Volts x Amps). For US appliances on standard outlets: amps x 120 = watts. A 10-amp microwave uses 1,200 watts. You can also buy a plug-in power meter ($15-30) for direct measurement.