DC Formula
A = W ÷ V
A 1,200 W DC load at 48 V draws 25 A under ideal steady-state conditions.
Single-Phase AC
A = W ÷ (V × PF)
A 2,000 W load at 240 V and 0.9 PF draws approximately 9.26 A. If PF were 1, current would be 8.33 A.
Three-Phase AC
A = W ÷ (√3 × VLL × PF)
A balanced 10 kW load at 480 V and 0.85 PF draws approximately 14.15 A. Use line-to-line voltage in this form.
Efficiency Matters
If watts describe mechanical output or another delivered output, convert to electrical input before finding current. Electrical input watts equal output watts divided by efficiency.
Calculated running current does not include motor starting, surge, harmonics, duty cycle, or code sizing factors.