How to use this tool
List each appliance's average watts, hours per day and number of days.
Enter your unit price and an optional comparison price. Standing charges and tiered tariffs need separate treatment.
Energy (kWh) = watts × hours × days / 1,000
Worked example
$18.30 · energy cost
Fixed example using the settings below. Monetary examples use USD; dates and times use their stated reference values. This example stays unchanged when you edit your calculation.
Example inputs
- Appliances: name, watts, hours/day, days: Lamp,10,5,30; Heater,1500,2,30
- Price per kWh: 0.2
- Comparison price per kWh: 0.15
Method illustration: 1,000 W used 2 hours/day for 30 days consumes 60 kWh.
Assumptions and limits
- Wattage is average power while operating; use measured energy for cycling appliances. Standing charges and tiered tariffs are excluded.
Check or report a result
Check the units, selected calculation and assumptions first. Compare the fixed example above with your inputs to identify what changed.
Report a calculation issue with the page address, hypothetical inputs, result displayed and result expected. Do not include passwords, bank details or other private information.