KVA Calculator

Calculating kVA (Apparent Power)

Kilovolt-amperes (kVA) measure apparent power in AC electrical systems. Unlike kilowatts (real power), kVA includes both real and reactive components and is used for transformer, generator, and breaker sizing.

Formulas

Single-phase:

$$kVA = \frac{V \times I}{1000}$$

Three-phase:

$$kVA = \frac{\sqrt{3} \times V \times I}{1000}$$

Real power with power factor:

$$kW = kVA \times PF$$

Practical Notes

Power factor (PF) ranges from 0 to 1 and reflects how efficiently apparent power performs useful work. Motors and inductive loads typically have PF below 1. Use line voltage for three-phase calculations.

Related tools: KVA to Amperage Calculator and Amps to kVA Calculator.

Frequently Asked Questions

What is the difference between kVA and kW?

kVA is apparent power (total electrical load). kW is real power (useful work). kW = kVA × power factor.

When do I use the three-phase formula?

Use the √3 formula for balanced three-phase systems where V is line-to-line voltage.

What power factor should I enter?

Use 1.0 for resistive loads. Motors often run between 0.7 and 0.95. Check equipment nameplates when available.

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Calculating kVA (Apparent Power)

Formulas

Practical Notes

Frequently Asked Questions

Related Tools

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