kW to kVA Calculator

In electrical systems, kilowatts (kW) measure the real power doing useful work, while kilovolt-amperes (kVA) measure the total apparent power a system must supply — and the gap between them matters when sizing generators, UPS units, and transformers. Enter your kilowatts and power factor into the kW to kVA Calculator to find the apparent power (kVA) your equipment demands. Secondary outputs include power factor (%) and reactive power (kVAR).

kW

Real power consumed by the electrical load

Ratio of real power to apparent power (typically 0.8-0.95)

Results

Apparent Power

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Power Factor (%)

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Reactive Power

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Frequently Asked Questions

What is the difference between kW and kVA?

kW (kilowatts) represents real power that actually performs work, while kVA (kilovolt-amperes) represents apparent power, which is the total power in an AC circuit including both real and reactive components.

What is power factor and why is it important?

Power factor is the ratio of real power (kW) to apparent power (kVA), ranging from 0 to 1. A higher power factor means more efficient power usage, while a low power factor indicates energy waste through reactive power.

How do you calculate kVA from kW?

The formula is: kVA = kW ÷ Power Factor. For example, if you have 10 kW with a power factor of 0.8, then kVA = 10 ÷ 0.8 = 12.5 kVA.

What is a typical power factor for electrical equipment?

Most electrical equipment operates with power factors between 0.8 to 0.95. Motors typically have 0.8-0.9, while resistive loads like heaters have a power factor close to 1.0.

Why is kVA important for transformer sizing?

Transformers are rated in kVA because they must handle the total apparent power, not just the real power. The transformer must be sized based on kVA to avoid overloading, regardless of the power factor.

What is reactive power and how is it calculated?

Reactive power (kVAR) is the power that oscillates between source and load without performing useful work. It can be calculated as: kVAR = kVA × sin(cos⁻¹(power factor)).

Can power factor be greater than 1?

No, power factor cannot exceed 1.0 in normal circumstances. A power factor of 1.0 represents perfect efficiency where all power is real power, with no reactive component.

How does poor power factor affect electricity costs?

Poor power factor increases current draw for the same amount of work, leading to higher transmission losses and potential utility penalties. Many utilities charge extra fees for power factors below 0.9.