⚡ Electrical Power Calculator
Calculate power (W), current (A), voltage (V), or resistance (Ω) — enter any two values.
Enter any 2 values — the other 2 will be calculated automatically.
Power Formulas
- P = V × I (Power = Voltage × Current)
- P = I² × R (Power = Current² × Resistance)
- P = V² / R (Power = Voltage² / Resistance)
- For AC: Apparent Power (VA) = V × I, Real Power (W) = V × I × Power Factor
- Efficiency = Output Power / Input Power × 100%
Frequently Asked Questions
What is power factor?
Power factor (0 to 1) represents how efficiently AC power is used. Resistive loads have PF=1. Motors and transformers typically have PF=0.7-0.9.
How many watts can a 15A circuit handle?
At 230V (India standard): 15A × 230V = 3,450W. But keep load under 80% = 2,760W for safety.