Watts to amps calculator for DC and AC

Circuit type Direct current (DC) Single-phase AC (RMS supply voltage) Balanced three-phase AC (line-to-line RMS)

Real power (W)

Voltage (V)

Power factor (0–1)

Dimensionless. Default 1.0 = unity power factor (editable — not silently assumed).

Calculate Copy current

— Choose a circuit type and enter watts and volts.

• DC: 1200 W / 120 V = 10 A
• 1φ AC: 1200 W / (120 V × 0.8) = 12.5 A
• 3φ AC: 12000 W / (√3 × 400 V × 0.8) ≈ 21.65 A

Steady-state mathematical estimate using real power (W). Not apparent power (VA). Does not size breakers, conductors, or protective devices. Does not claim NEC compliance or installation safety.

DC: I=P/V. 1φ AC: I=P/(V·PF). 3φ: I=P/(√3·V_LL·PF). Example: 1200 W / 120 V DC = 10 A; 1200 W @ 120 V · PF 0.8 = 12.5 A. Real power (W), not VA. Not breaker or wire sizing.