kVA (kilovolt-ampere) is the unit of apparent power in an AC circuit. It represents the total power supplied by the source, combining both real power (kW) that does useful work and reactive power (kVAR) consumed by inductive or capacitive loads.

What formula is used for single-phase circuits?

For single-phase AC: S(kVA) = I(A) × V(V) / 1000. Multiply the current by the voltage and divide by 1000 to convert volt-amperes to kilovolt-amperes.

What formula is used for three-phase circuits?

For three-phase AC: S(kVA) = √3 × I(A) × V(V) / 1000. The √3 factor (approximately 1.7321) accounts for the three-phase relationship. The voltage entered should be the line-to-line voltage.

What is the difference between kVA and kW?

kVA is apparent power — the total power drawn from the supply. kW is real power — the portion that performs actual work. They are related by the power factor: kW = kVA × PF. For purely resistive loads, PF = 1 and kW equals kVA.

Why is kVA used instead of kW for sizing equipment?

Transformers, generators, and UPS systems are rated in kVA because they must supply the full apparent power regardless of the load's power factor. Using kVA ensures the equipment is not undersized when inductive loads are present.

Does this calculator apply to DC circuits?

kVA is an AC concept only — it does not apply to DC circuits because there is no reactive power or phase difference in DC. For DC, use the simple formula P(W) = I(A) × V(V) and convert to kW by dividing by 1000.

Amps to kVA Calculator

Name: Amps to kVA Calculator
Availability: InStock
Author: Nham Vu

Convert amperes (A) to kilovolt-amperes (kVA) for single-phase or three-phase AC circuits instantly.

Circuit Parameters

Circuit Type

Current (A)

Voltage (V) (line-to-neutral)

Result

Enter values and press Calculate

Formula Reference

Single-Phase AC

kVA = A × V / 1000

V is line-to-neutral voltage

Three-Phase AC

kVA = √3 × A × V / 1000

V is line-to-line voltage

Result copied!

Summary

Convert amperes (A) to kilovolt-amperes (kVA) for single-phase or three-phase AC circuits instantly.

How it works

Select your circuit type: single-phase AC or three-phase AC.
Enter the current in amperes (A).
Enter the voltage in volts (V).
The calculator applies the correct formula and displays the result in kVA.
A breakdown table shows input values, formula used, and the computed result.
Use the Reset button to start a new calculation.

Use cases

Size transformers and generators based on load current and voltage.
Determine UPS or inverter capacity requirements for critical equipment.
Calculate the apparent power of three-phase industrial motors.
Specify switchgear and circuit protection ratings.
Compare kVA ratings between single-phase and three-phase configurations.
Estimate panel board capacity for new electrical installations.
Convert nameplate current to kVA for equipment procurement.
Plan electrical service upgrades for commercial buildings.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu