Watts to amps calculator
Enter the load and voltage. Leave power factor at 1 for heaters, kettles, lighting and anything purely resistive; use 0.8 to 0.9 for motors, transformers and switch-mode supplies unless the nameplate says otherwise.
- Current
- 8.33 A
Use power factor 1 for resistive loads such as heaters and incandescent lamps, and 0.8 to 0.9 for motors unless the nameplate says otherwise.
The wattage formulas
DC and single-phase resistive: P = V x I, so I = P / V and V = P / I.
Single-phase AC with a reactive load: P = V x I x PF, so I = P / (V x PF).
Three-phase AC: P = 1.732 x V x I x PF, so I = P / (1.732 x V x PF), with V line to line.
Combined with Ohm's law these give the other forms people search for: P = I² x R and P = V² / R. They are all the same relationship rearranged.
Common loads in amps
Resistive loads at power factor 1. These are the figures for choosing a breaker or checking whether an extension lead is rated for the job.
| Watts | 120 V | 230 V | 240 V |
|---|---|---|---|
| 100 | 0.83 | 0.43 | 0.42 |
| 400 | 3.33 | 1.74 | 1.67 |
| 600 | 5.00 | 2.61 | 2.50 |
| 1,000 | 8.33 | 4.35 | 4.17 |
| 1,500 | 12.50 | 6.52 | 6.25 |
| 2,000 | 16.67 | 8.70 | 8.33 |
| 3,000 | 25.00 | 13.04 | 12.50 |
| 5,000 | 41.67 | 21.74 | 20.83 |
