Electricity Bill Calculator
Find out what an appliance actually costs to run, or estimate a full monthly electricity bill from usage and your rate per kWh.
Your numbers
Check the label on the appliance, or use your whole home's average draw.
National average is around $0.16/kWh — check your latest bill for your real rate.
Estimated Monthly Cost
$21.60/mo
$259.20/yr
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Last updated: August 25, 2026 · Reviewed by the DoCalc team
What This Calculator Answers
Electricity bills are confusing because a single number on the bill hides dozens of different appliances running at different wattages, for different hours, at a rate that's rarely stated in plain terms. This tool flips that around: give it a wattage, how long something runs, and your rate per kWh, and it tells you the real cost — whether that's a single space heater, an AC unit, or your estimate of a whole home's average draw.
The Formula
Watts are converted to kilowatts (÷ 1000) because utilities bill in kilowatt-hours, not watt-hours — a 1500W device is 1.5 kW, and running it for one hour uses 1.5 kWh.
Worked Example
A 1500W space heater run 3 hours a day, 30 days a month, at a $0.16/kWh rate: 1.5 kW × 3 hours = 4.5 kWh/day, × 30 days = 135 kWh/month, × $0.16 = $21.60/month just for that one appliance — a useful number to compare against buying a more efficient model or changing usage habits.
Finding Your Real Numbers
Wattage is usually printed directly on the appliance's label or nameplate, in its manual, or on the manufacturer's spec page — if only volts and amps are listed, multiply them together to get watts. Your rate per kWh is on your electricity bill, usually listed as the energy charge per unit; if your bill only shows a total dollar amount, divide it by the total kWh used that period to back into your effective rate.
Worth knowing: Many utilities also add a flat monthly service or connection charge on top of usage — enter it in the optional field to match your real bill total, or leave it at zero to see pure energy cost.
Common Mistakes to Avoid
The most common mistake is using an appliance's rated maximum wattage (often printed larger on the label) instead of its typical running wattage — many appliances, especially those with motors or heating elements, cycle on and off and use less on average than their peak draw. A second mistake is forgetting standby/phantom power for electronics left plugged in — small, but it adds up across a household. A third is mixing up daily and monthly figures when comparing this tool's output to a monthly bill.
Frequently Asked Questions
How do I calculate the cost of running an appliance?
Multiply the appliance's wattage by the hours you use it per day, divide by 1000 to get kWh, then multiply by your electricity rate per kWh. A 1500W heater run 3 hours a day at $0.16/kWh costs about $0.72/day.
Where do I find my appliance's wattage?
Check the label or nameplate on the appliance itself, its user manual, or the manufacturer's spec sheet online — wattage is usually listed directly, or you can calculate it from volts × amps if only those are given.
Where do I find my electricity rate per kWh?
Check a recent electricity bill — most utilities list a per-kWh rate directly, or you can divide your total energy charge by your total kWh usage for that billing period.
What's a typical electricity rate in the US?
Around $0.16 per kWh on average nationally as of 2026, but this varies enormously by state and utility — from under $0.10/kWh in some areas to over $0.30/kWh in others.
What is the fixed monthly charge field for?
Many utilities charge a flat monthly service/connection fee in addition to per-kWh usage — enter it if you want the total to match your actual bill; leave it at 0 to see pure energy cost.