Electrical Engineering
Power Consumption Calculator ⚡ P = V × I
Calculate power consumption, energy usage, and cost for electrical devices.
Device / Appliance
Select a device or choose Custom for manual entry
Voltage (V)
V
Supply voltage (230V typical, 120V US)
Current (I)
A
Current draw in amperes
Power (P)
W
Power consumption in watts (calculated from V×I)
Usage Hours per Day
h/day
Active usage hours per day
Standby Power
W
Power consumed when in standby mode
Electricity Rate
$ /kWh
Cost per kilowatt-hour (kWh)
Days Used per Month
days
Number of days the device is used per month
Power 0W
Monthly Energy
0 kWh
including standby
Active Power 0 W
Daily Energy 0 kWh
Monthly Cost $0
Standby Cost $0

📊 Detailed Breakdown

Parameter Value Unit

How the formula works

P = V × I  |  Energy (kWh) = Power (kW) × Time (h)  |  Cost = Energy × Rate
  • Power (W) = Voltage (V) × Current (A)
  • Active Energy (kWh) = (Power × Hours) / 1000
  • Standby Energy (kWh) = (Standby Power × (24 − Hours) × Days) / 1000
  • Total Energy = Active Energy + Standby Energy
  • Monthly Cost = Total Energy × Electricity Rate
  • Standby Cost = Standby Energy × Electricity Rate
  • Power factor not included (assumes unity for simplicity)
  • Typical standby power: TV (5W), Computer (3W), Charger (1W)