Input Parameters
Enter current, voltage, and select circuit type.
About This Calculator
- DC: P = I × V
- Single-phase AC: P = I × V × PF
- Three-phase AC: P = √3 × I × V × PF
- Outputs: Active power (W/kW), apparent power (VA), reactive power (VAR)
How this amps to watts converter works
The conversion between amperes (current) and watts (power) is based on the power formula P = V × I. In DC circuits, power equals current multiplied by voltage directly.
For AC circuits, the power factor (PF) must be considered. Single-phase AC uses P = I × V × PF, while three-phase AC uses P = √3 × I × V × PF (with line-to-line voltage).
Inputs explained
- Current (A): The electrical current flowing through the circuit.
- Voltage (V): For DC — supply voltage. For AC — RMS voltage (line-to-line for three-phase).
- Power Factor: Ratio of active to apparent power (0–1). Pure resistive loads ≈ 1.0, motors typically 0.7–0.9.
FAQ
What formula converts amps to watts for AC circuits?
Single-phase: P = I × V × PF. Three-phase: P = √3 × I × V × PF. The power factor accounts for the phase difference between voltage and current.
How many watts is 10 amps at 220V?
DC: 10 × 220 = 2,200W. Single-phase AC (PF=0.95): 10 × 220 × 0.95 = 2,090W. Three-phase AC (PF=0.95): √3 × 10 × 220 × 0.95 ≈ 3,620W.
Why does three-phase use √3?
The √3 factor (≈1.732) comes from the relationship between line voltage and phase voltage in a balanced three-phase system: V(L-L) = √3 × V(L-N).