Watts to Amps Calculator
Convert real power (watts) to current (amps) for single- or three-phase supply.
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What this tool does
Convert real power (watts) to current (amps) for single- or three-phase supply. Three-phase uses line-to-line voltage and assumes a balanced load. Single phase uses the two-wire supply voltage.
How to use the Watts to Amps Calculator
- Enter or select real power (watts).
- Enter or select voltage.
- Enter or select supply.
- Enter or select power factor.
- Read the calculated result; change any measurement to compare alternatives.
Formula
amps = watts/(phase factor×voltage×power factor)
- amount
- Real power (watts)
- voltage
- Voltage
- phase
- Supply
- pf
- Power factor
Three-phase uses line-to-line voltage and assumes a balanced load. Single phase uses the two-wire supply voltage.
Worked example
For watts to amps calculator, the following measurements illustrate the exact method: Real power (watts): 1200; Voltage: 240; Supply: 1; Power factor: 0.9.
Inputs
- Real power (watts)1200
- Voltage240
- SupplySingle phase
- Power factor0.9
Result
- Current (amps)5.56
Results explained
- Current (amps)
- Current (amps) from the formula above. Three-phase uses line-to-line voltage and assumes a balanced load. Single phase uses the two-wire supply voltage.
Frequently asked questions
amps = watts/(phase factor×voltage×power factor)
Three-phase uses line-to-line voltage and assumes a balanced load. Single phase uses the two-wire supply voltage.
No. Electrical and HVAC results are estimates. Installation must comply with local codes and be checked by a qualified licensed professional.
Nameplate values, conductor temperature, power factor, efficiency, weather and actual installation conditions may differ from your entered assumptions.
Confirm units, manufacturer data and the formula's assumptions, then verify sizing with the equipment instructions and applicable local standards.