💡 Electricity Calculator
Every appliance's cost is watts times hours divided by 1000 (kilowatt-hours), times your electricity rate. Enter the three numbers and see the daily and monthly damage.
Great for comparing old vs efficient appliances: a 60 W bulb left on all evening costs real money over a month.
How to use this calculator
Enter an appliance's wattage, how many hours a day it runs, and your electricity rate to see its daily and monthly cost.
- Enter the Power in watts from the appliance label.
- Enter the Hours per day it typically runs.
- Enter your Electricity rate per kWh from your bill.
- Read the monthly cost, plus daily and monthly energy use.
Frequently asked questions
What formula does the Electricity Calculator use?
Daily kilowatt-hours equal watts times hours divided by 1000. Monthly energy assumes 30 days, and cost equals monthly kWh times your rate.
Can you give a worked example?
A 100 watt device running 8 hours a day uses 0.8 kWh daily and 24 kWh monthly, costing $3.60 per month at $0.15 per kWh.
Where do I find my electricity rate?
On your utility bill, listed as the price per kWh. Rates vary widely by country and provider, so use your own number.
Why is the month 30 days?
Thirty days is the standard estimating convention. Your actual bill period may be a day or two longer or shorter.