Amps to VA Calculator - Apparent Power from Current

Editorially reviewed Reviewed by Agarapu Ramesh, science educator (chemistry). LinkedIn

Last reviewed: May 2026 | Standard electrical engineering formulas

VA is what the wires and transformer have to carry. It is volts multiplied by amps, with sqrt(3) added for three-phase line values. Do not include power factor here. That comes later when you convert VA to watts.

Formula at a glance

single-phase: VA = V x A
three-phase: VA = 1.732 x V x A
kVA = VA / 1000

Field note: VA can look bigger than watts, and that is not a mistake. Low power factor equipment pulls current that does not become useful real power.

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Amps to VA Calculator

Convert current to apparent power

Phase

Result

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Formulas

1φVA = I × V

3φVA = I × V × √3

VA vs Watts

VA = Apparent power
W = Real power
W = VA × PF
For resistive loads, VA = W

How to use the Amps to VA Calculator

Use this as a fast electrical check, then compare the result with the nameplate, measured voltage and power factor. The formula is clean. Real panels, motors and UPS loads usually have one extra wrinkle.

Worked example

Example: 10 A at 120 V is 1,200 VA. A 20 A load on 415 V three-phase is 14,376 VA, or 14.38 kVA.

Practical checks before you trust the number

Use VA for UPS, inverter and transformer sizing.
Use watts or kW when you care about real work and electricity bills.
Three-phase calculations use line-to-line voltage, not phase-to-neutral voltage.

Common mistake

VA can look bigger than watts, and that is not a mistake. Low power factor equipment pulls current that does not become useful real power.

Sources and references

OSHA Electrical Standards overview - Safety baseline for electrical work and workplace electrical hazards.
OpenStax - Electrical energy and power - Explains P = IV and the relationship between energy, time and power.
NIST Glossary - Watt - Defines the watt as one joule per second.
ORNL Power Factor training - Shows why power factor matters in AC and three-phase calculations.

Related calculators

Frequently Asked Questions

For single-phase, multiply volts by amps. For 3-phase, multiply 1.732 by line volts by amps.

No. VA is apparent power, so power factor is not used until converting to watts or kW.

Use line-to-line voltage, such as 400 V or 415 V depending on the system.

Yes. Multiply the VA result by power factor to estimate watts.