Home & Garden
Electricity cost calculator
Estimate how much electricity an appliance uses and what it may cost per month or year.
- W or kW input
- kWh per day and month
- Monthly and yearly cost
Formula and method
Electricity cost formula
kWh = watts ÷ 1000 × hours; cost = kWh × tariffDaily kWh is watts converted to kilowatts multiplied by hours per day.
Monthly cost multiplies monthly kWh by your electricity tariff.
Assumptions
- Power draw is treated as constant.
- Tariff is your all-in cost per kWh.
- Actual usage can vary by cycle, thermostat, or load.
Practical examples
Space heater
1,200 W for 2 hours/day at $0.18/kWh
About 72 kWh/month and $13/month60 W bulb
60 W for 5 hours/day
Low monthly kWh but useful for comparisonFAQ
Should tariff include delivery charges?
Use an all-in kWh rate when possible for a more realistic estimate.
Does this handle variable power?
Use average power if the appliance cycles on and off.
Can I estimate yearly cost?
Yes. The yearly cost is monthly cost multiplied by 12.
What appliances can I calculate?
Heaters, computers, bulbs, washing machines, chargers, pumps, and other electric devices.