I = P / VNo power factor needed for DC circuits.
Watt Value Calculator
400 Watts to Amps Calculator
Find the current in amps for a 400 watt load. Select the circuit voltage and system type below — DC, single-phase AC, or three-phase AC — and the calculator shows the result instantly. The table below lists results at common voltages.
Conversion direction
Quick voltage presets
Power factor varies by load. Use the equipment value when available.
Calculated result1000 W · 120 V · DC
8.333 A
Formula used
I = P / VCustom voltage is always supported.
400 Watts to Amps — Conversion Table
Results at common voltages. AC values use power factor = 0.9.
| Voltage | DC (I = P/V) | AC 1φ (PF 0.9) | AC 3φ (PF 0.9) |
|---|---|---|---|
| 12 V | 33.3333 A | 37.037 A | 21.3833 A |
| 24 V | 16.6667 A | 18.5185 A | 10.6917 A |
| 48 V | 8.3333 A | 9.2593 A | 5.3458 A |
| 120 V | 3.3333 A | 3.7037 A | 2.1383 A |
| 240 V | 1.6667 A | 1.8519 A | 1.0692 A |
Formulas Used
I = P / (V × PF)Single-phase AC — multiply voltage by power factor.
I = P / (√3 × V × PF)Three-phase AC — divide by √3 ≈ 1.732.
Frequently Asked Questions
How many amps is 400 watts at 120V?
DC or resistive: 400 / 120 = 3.3333 A. Single-phase AC at PF 0.9: 400 / (120 × 0.9) = 3.7037 A.
How many amps is 400 watts at 240V?
DC or resistive: 400 / 240 = 1.6667 A. Single-phase AC at PF 0.9: 400 / (240 × 0.9) = 1.8519 A.
How many amps is 400 watts at 12V?
DC: 400 / 12 = 33.3333 A. This is common for 12V battery and solar systems.