VastCalc
Conversion
Watts to Amps Converter
Convert watts to amps, milliamps, volt-amps, and BTU/hr for DC and single-phase AC circuits.

Watts to Amps Converter

Convert electrical power in watts to current in amps for DC and single-phase AC circuits. Enter the wattage, voltage, and power factor to calculate the current draw, apparent power, and thermal output of any electrical device or circuit.

The relationship between watts, amps, and volts follows Ohm's law and the power equation. For DC circuits and purely resistive AC loads (power factor = 1), the formula is simply Amps = Watts / Volts. For AC circuits with inductive or capacitive loads, the power factor must be included.

Key formulas:

  • Amps (DC) = Watts ÷ Volts
  • Amps (AC single-phase) = Watts ÷ (Volts × Power Factor)
  • Apparent Power (VA) = Watts ÷ Power Factor
  • BTU/hr = Watts × 3.41214

Common Electrical Reference:

Device Watts Voltage PF Amps
LED Bulb 10 120 V 1.0 0.083
Microwave 1,000 120 V 0.95 8.77
Hair Dryer 1,500 120 V 1.0 12.5
Window AC 1,200 120 V 0.85 11.76
Electric Oven 2,400 240 V 1.0 10.0
EV Charger (L2) 7,200 240 V 1.0 30.0

The power factor describes how efficiently an AC circuit uses power. Purely resistive loads (heaters, incandescent bulbs) have a PF of 1.0. Motors, compressors, and fluorescent lighting typically have PFs of 0.8-0.95, meaning they draw more current than the wattage alone would suggest.

Frequently Asked Questions

Search Calculators

Search across all calculator categories