Amps to Watts Calculator
Choose the supply type, then enter current and voltage to get the power in watts.
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Formula
- DC:
W = V × A - AC single-phase:
W = V × A × PF - AC three-phase (line-to-line voltage):
W = √3 × V × A × PF - Apparent power:
VA = V × A(single-phase) or√3 × V × A(three-phase).
Worked example
Single-phase, 10 A at 230 V, power factor 0.9: apparent power 230 × 10 = 2300 VA, real power 2300 × 0.9 = 2070 W (2.07 kW).
Three-phase, 10 A at 400 V, power factor 0.8: 1.7320508 × 400 × 10 = 6928.20 VA, times 0.8 = 5542.56 W.
DC, 5 A at 12 V: 60 W.
Frequently asked questions
How do I convert amps to watts?
For DC, watts = amps × volts: 5 A at 12 V is 60 W. For single-phase AC, also multiply by the power factor: 10 A at 230 V and 0.9 PF is 2070 W.
How do I convert amps to watts for three-phase?
Use watts = √3 × line-to-line volts × amps × power factor. For 10 A at 400 V and 0.8 PF that is 1.732 × 400 × 10 × 0.8 = 5542.56 W.
What power factor should I use?
Resistive loads such as heaters are close to 1. Motors and many power supplies are often 0.7 to 0.95; check the rating plate. The power factor is ignored for DC.
What is the difference between watts and VA?
VA is apparent power (volts × amps) and watts is the real power doing work. At 0.9 PF, 2300 VA is 2070 W. This calculator is for learning and design checks only. It is not a safety certification: wiring, breaker and cable sizing must follow your local electrical code and be checked by a qualified electrician.