Watts to Amps Calculator
Find current in amps from power in watts and voltage — DC, AC single-phase, or three-phase.
How the conversion works
Amps measure electric current, watts measure power, and volts measure potential. For a DC circuit the relationship is simply current = power ÷ voltage (I = P ÷ V).
AC circuits add a power factor, and three-phase systems add a √3 factor. This calculator handles all three so you can size wiring, breakers, and chargers correctly.
I(A) = P(W) ÷ V(V) (DC)
I(A) = P(W) ÷ (V × PF) (AC single phase)
I(A) = P(W) ÷ (√3 × V × PF) (AC three phase)PF is the power factor (1 for purely resistive loads, ~0.8 for many motors).
Conversion table
| Power | At 12 V | At 120 V | At 240 V |
|---|---|---|---|
| 100 W | 8.33 A | 0.833 A | 0.417 A |
| 500 W | 41.67 A | 4.17 A | 2.08 A |
| 1,000 W | 83.33 A | 8.33 A | 4.17 A |
| 1,500 W | 125 A | 12.5 A | 6.25 A |
| 2,000 W | 166.7 A | 16.67 A | 8.33 A |
| 3,000 W | 250 A | 25 A | 12.5 A |
Frequently asked questions
How do you convert watts to amps?
Divide power in watts by voltage in volts: amps = watts ÷ volts. For AC, also divide by the power factor; for three-phase, divide by √3 × volts × power factor.
How many amps is 1500 watts at 120 V?
On a 120 V DC or resistive circuit, 1,500 W ÷ 120 V = 12.5 amps.
What is power factor?
Power factor is the ratio of real power to apparent power in an AC circuit. Resistive loads are about 1.0; motors and many electronics are around 0.8.