Amps to kVA Calculator — Single-Phase and Three-Phase

Calculator

An amps to kVA calculator finds apparent power from current and voltage using kVA = V × I / 1000 for single-phase and kVA = √3 × V × I / 1000 for three-phase circuits.

Amps to kVA Calculator

Runs in this browserUses the displayed formula

Inputs are calculated only in this browser. Three-phase uses line-to-line voltage; if the power factor is unknown, use 1 for resistive loads and 0.8-0.9 for motors.

Examples

Phase

Current

Voltage

Apparent power

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What is it

Knowing load current and voltage lets you calculate apparent power (kVA) to size transformers and generators. Apparent power does not depend on power factor, so it can be calculated without knowing the load characteristics; real power (kW) is apparent power times the power factor. Three-phase circuits multiply by √3 using line-to-line voltage.

Single-phase: kVA = V × I / 1000 · Three-phase: kVA = √3 × V × I / 1000

How to use

1Pick single-phase or three-phase.
2Enter current (A) and voltage (V).
3Press calculate to get the apparent power in kVA.

Reference

Amps to kVA Calculator — Single-Phase and Three-Phase Reference
Current	Condition	Capacity
30A	1-phase 220V	6.6kVA
30A	3-phase 380V	19.74kVA
100A	3-phase 480V	83.14kVA

Sources & standards

BIPM — The International System of Units (SI Brochure) - BIPM
IEC Electropedia — International Electrotechnical Vocabulary - IEC
MDN Web Docs: Client-side web APIs - MDN Web Docs

FAQ

How many kVA is a 30A load at 220V single-phase?

kVA = 220 × 30 / 1000 = 6.6 kVA. At 380V three-phase it is √3 × 380 × 30 / 1000 ≈ 19.74 kVA.

Why are transformers rated in kVA instead of kW?

Transformer winding heat depends on voltage and current regardless of power factor, so capacity is stated as apparent power (kVA) independent of the load power factor.

Is amps to kVA input sent to a server?

No. This calculator runs in your browser and does not send input to a server.