How to convert watts to amps
For DC, divide power in watts by voltage. AC calculations can also require power factor and a phase multiplier.
Example
A 1,200-watt DC load at 120 volts draws 10 amps.
Use equipment specifications and applicable electrical requirements when sizing circuits, conductors or protection devices.
Frequently asked questions
How many amps is 1,200 watts at 120 volts?
For DC, 10 amps.
Why does AC need power factor?
Real power in AC systems can differ from apparent power because voltage and current may not be perfectly aligned.
Is three-phase current calculated differently?
Yes. Balanced three-phase power calculations use a square-root-of-three factor.
Using this calculator effectively
The watts-to-amps calculator rearranges the power relationship to estimate current from watts and voltage. It supports DC, single-phase AC and balanced three-phase AC with power factor where applicable.
Common uses
- Estimating current draw from a known wattage and voltage.
- Comparing current at different supply voltages.
- Checking an approximate AC current when power factor is known.
Tips for a better estimate
- Select the correct circuit type before using the result.
- Use real power in watts, not apparent power in VA, unless the formula and inputs are adjusted appropriately.
- Do not size protective devices or conductors from this calculation alone.
Related calculations
Amps to Watts Calculator · Ohm's Law Calculator · Voltage Drop Calculator