Why do I need power factor?

Watts measure real power - the energy actually doing work. Volt-amps measure apparent power - voltage times current. For pure resistive loads (heaters, incandescent bulbs) the two are equal and PF = 1.0. For motors, transformers, and most electronic ballasts, PF is less than 1.0 and you cannot convert kVA to kW (or amps to watts) without it.

Why √3 for three-phase?

In a balanced three-phase system, the line-to-line voltage is √3 times the line-to-neutral voltage, and the three phases are 120° apart. Working through the geometry leaves a √3 (about 1.732) factor in the power equation.

Does this work for DC?

Yes for the W = V × I conversions (DC has no power factor and no phase). Skip the phase selector and use a power factor of 1.0.

Electrical Unit Converter

Convert between watts, amps, volts, kW, kVA, and horsepower. Supports single-phase and three-phase calculations.

Inputs

Power

Voltage

Power Factor

Phase

Single-PhaseThree-Phase

Result

Current

8.333A

I = P / (V × PF) = 1000 / (120 × 1)

About this calculator

Electricians juggle a dozen related units: amps, volts, watts, kilowatts, kVA, horsepower, and BTUs per hour. Most everyday problems boil down to converting between two of them given a third. This converter handles the common pairings for both single-phase and three-phase circuits, with adjustable power factor for kVA and horsepower conversions.

Formula

Power equals voltage times current for DC and resistive single-phase loads. Three-phase systems multiply by √3. Real power (watts) equals apparent power (VA) times the power factor, which is why kVA conversions need a power factor input.

Single-phase: W = V × I × PF
Three-phase: W = √3 × V × I × PF
Apparent power: VA = V × I (single-phase) or √3 × V × I (three-phase)

How to use

Pick the conversion you need from the unit selectors.
Choose single-phase or three-phase if it applies.
Enter the known values - voltage, current, or power.
Adjust power factor if your load is not purely resistive (motors typically run 0.8 to 0.9).
Read the converted result in your target unit.

Worked example

Setup

A three-phase 480-volt motor draws 12 amps with a 0.85 power factor. How many kilowatts is it consuming?

Calculation

kW = (√3 × 480 × 12 × 0.85) ÷ 1000 = (1.732 × 480 × 12 × 0.85) ÷ 1000 = 8,478 W ÷ 1000 = 8.48 kW.

Answer

The motor pulls roughly 8.5 kW of real power. Its apparent power (kVA) is 9.98, and the difference is reactive power burned by the motor windings.

Frequently asked questions

Why do I need power factor?: Watts measure real power - the energy actually doing work. Volt-amps measure apparent power - voltage times current. For pure resistive loads (heaters, incandescent bulbs) the two are equal and PF = 1.0. For motors, transformers, and most electronic ballasts, PF is less than 1.0 and you cannot convert kVA to kW (or amps to watts) without it.
Why √3 for three-phase?: In a balanced three-phase system, the line-to-line voltage is √3 times the line-to-neutral voltage, and the three phases are 120° apart. Working through the geometry leaves a √3 (about 1.732) factor in the power equation.
Does this work for DC?: Yes for the W = V × I conversions (DC has no power factor and no phase). Skip the phase selector and use a power factor of 1.0.