kWh Cost Calculator
Calculate the daily, monthly, and annual cost of running an appliance from its wattage, hours used per day, and electricity price.
W
hours
$
/ kWh
Results
Daily Cost
$0.45
Daily Energy Use
3.000 kWh
Monthly Cost
$13.50
Annual Cost
$164.25
How Does the kWh Cost Calculator Work?
Enter an appliance's wattage, how many hours a day you run it, and your electricity price per kilowatt-hour. The calculator converts watts to kilowatts, multiplies by hours used to get daily energy consumption in kWh, and multiplies that by your electricity price to get the daily cost. It then scales that daily cost up to monthly (×30) and annual (×365) figures.
Example
A 1,500W space heater run for 2 hours a day uses 3 kWh daily. At $0.15 per kWh, that costs $0.45 a day, about $13.50 a month, and roughly $164.25 a year — just from that one appliance.
Common Use Cases
- Finding out which appliance is driving up an electricity bill.
- Deciding whether a more energy-efficient replacement appliance is worth the upfront cost.
- Estimating the added cost of running a space heater, AC unit, or pool pump.
- Budgeting electricity costs for a home office setup or server/gaming PC.
FAQs
Where do I find an appliance's wattage?
Check the label or nameplate on the appliance itself, its manual, or the manufacturer's spec sheet — it's usually listed in watts (W). If only amps and voltage are given, wattage equals amps × voltage.
Does this account for standby power when the appliance is off?
No — this calculator only estimates active-use cost based on the hours you specify. Many electronics draw a small amount of standby ("phantom") power even when off or idle, which isn't included here.
Where do I find my electricity price per kWh?
Check a recent utility bill — it's usually listed as a per-kWh rate, sometimes broken into tiers or time-of-use periods. Use your average or peak rate depending on when the appliance typically runs.