Electrical Power Calculator
Calculate real power, apparent power, and power factor efficiency for AC and DC circuits.
Real Electrical Power (P)
—
—
How to Calculate Electrical Power in Watts & Kilowatts
- Enter Voltage and Current, or Current and Resistance.
- Select DC (Direct Current) or AC single-phase circuit.
- View the active power in Watts (W) and Kilowatts (kW).
Power Formulas
-
DC Power:
P = V × I -
AC Single Phase:
P = V × I × Power Factor (cos φ)
Example
-
A 120V microwave drawing 10A of current consumes
120 × 10 = 1,200 Watts (1.2 kW).
Common Applications
- Estimating household electrical appliance power consumption.
- Generator and uninterruptible power supply (UPS) sizing.
- Data center server rack power budgeting.
Frequently Asked Questions
What is Power Factor in AC systems?
Power factor is the ratio of real working power (Watts) to apparent power (Volt-Amperes), reflecting inductive/capacitive phase shift.
How many watts is 1 kilowatt?
One kilowatt (kW) equals exactly 1,000 Watts.