Amps to Watts Calculator
Convert current to power for DC, single-phase, and three-phase circuits — with power factor for motors and electronics.
Common: 120 / 240 V (US), 230 V (EU/UK), 208 / 400 / 480 V (three-phase).
1.0 for heaters and resistive loads; 0.8–0.9 typical for motors.
Real power
0 W
W = A × V
Planning estimates only — verify with equipment nameplates and a licensed electrician for installations.
How to convert amps to watts
Power is current times voltage. The exact formula depends on the circuit:
- DC: W = A × V
- AC single-phase: W = A × V × PF
- AC three-phase: W = √3 × A × Vline-line × PF ≈ 1.732 × A × V × PF
Quick reference at power factor 1.0:
| Amps | Watts @ 12 V DC | Watts @ 120 V | Watts @ 230 V | Watts @ 240 V |
|---|---|---|---|---|
| 1 A | 12 W | 120 W | 230 W | 240 W |
| 5 A | 60 W | 600 W | 1,150 W | 1,200 W |
| 10 A | 120 W | 1,200 W | 2,300 W | 2,400 W |
| 15 A | 180 W | 1,800 W | 3,450 W | 3,600 W |
| 20 A | 240 W | 2,400 W | 4,600 W | 4,800 W |
| 30 A | 360 W | 3,600 W | 6,900 W | 7,200 W |
| 50 A | 600 W | 6,000 W | 11,500 W | 12,000 W |
Amps to watts FAQ
How do I convert amps to watts?
Watts = amps × volts. A 10 A load at 120 V is 1,200 W. For non-resistive AC loads multiply by power factor; for three-phase, W = √3 × A × V × PF.
How many watts is 15 amps at 120 volts?
1,800 W — the theoretical max of a US 15 A circuit. Code limits continuous loads to 80%, about 1,440 W.
What is power factor and when do I need it?
The ratio of real watts to volt-amps (0–1). Heaters ≈ 1.0; motors, fluorescent lighting, and electronics run 0.7–0.95. Skipping it overestimates real power for those loads.
How is DC different from AC for this conversion?
DC: W = A × V. Single-phase AC: W = A × V × PF. Three-phase AC: W = √3 × A × V(line-line) × PF.