Watts to Amps Calculator
Choose the supply type, then enter power and voltage to get the current in amps.
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Formula
- DC:
A = W ÷ V - AC single-phase:
A = W ÷ (V × PF) - AC three-phase (line-to-line voltage):
A = W ÷ (√3 × V × PF) - Apparent power:
VA = W ÷ PF.
Worked example
Single-phase, 2070 W at 230 V, power factor 0.9: 2070 ÷ (230 × 0.9) = 10 A; apparent power 2070 ÷ 0.9 = 2300 VA.
Three-phase, 5000 W at 400 V, power factor 0.8: 5000 ÷ (1.7320508 × 400 × 0.8) = 9.02 A.
DC, 60 W at 12 V: 5 A.
Frequently asked questions
How do I convert watts to amps?
For DC, amps = watts ÷ volts: 60 W at 12 V draws 5 A. For single-phase AC, divide by volts × power factor: 2070 W at 230 V and 0.9 PF draws 2070 ÷ 207 = 10 A.
How do I convert watts to amps for three-phase?
Use amps = watts ÷ (√3 × line-to-line volts × power factor). For 5000 W at 400 V and 0.8 PF: 5000 ÷ (1.732 × 400 × 0.8) = 9.02 A per phase.
Why does a lower power factor mean more amps?
The same real power needs more current when less of it does useful work. 2070 W at 230 V draws 9 A at PF 1 but 10 A at PF 0.9.
Can I use this to size a breaker or cable?
Only as a rough first figure. Protective devices and cables need margins for start-up current, ambient temperature and code rules. 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.