Amps to Volt-Amps (VA) Conversion Calculator

What amps to VA gives you

Volt-amps is apparent power — the plain product of voltage and current in an AC circuit. UPS units, power strips, isolation transformers, and control transformers are rated in VA because that’s the current-handling job they have to do, whether or not that current does useful work. If you know a load’s current, converting it to VA lets you check it against one of those ratings.

No power factor is needed. That’s the point of a VA rating: it stays valid regardless of the load’s power factor, so the manufacturer doesn’t have to guess what you’ll plug in.

The amps to VA formula

Single-phase:

Three-phase, line-to-line voltage:

is voltage, is current in amps. The √3 in the three-phase form accounts for the 120° spacing of the three line currents.

Worked example

The calculator’s defaults are 10 A at 120 V, single-phase.

The load presents 1,200 VA. On a three-phase 208 V circuit, the same 10 A per line would be VA.

Amps to Volt-Amps (VA) Conversion Calculator worked example diagram — A visual read of the worked example above — the same numbers the calculator returns for its default inputs.

Amps to VA reference (single-phase)

Current	120 V	208 V	240 V
1 A	120 VA	208 VA	240 VA
5 A	600 VA	1,040 VA	1,200 VA
10 A	1,200 VA	2,080 VA	2,400 VA
15 A	1,800 VA	3,120 VA	3,600 VA
20 A	2,400 VA	4,160 VA	4,800 VA

Sizing a UPS or power strip

A UPS has two independent limits — a VA rating and a watt rating — and the smaller one governs. For a computer load with a power-factor-corrected supply, the watt and VA figures are close, so either can be the limit. For a load with a poorer power factor, the VA limit is reached first. Convert your load’s current to VA with this calculator, then confirm it sits under both of the UPS’s ratings.

Common mistakes

Treating VA as watts. They match only for a resistive load; otherwise VA is higher.
Dropping the √3 for three-phase.
Using nominal voltage when the real supply voltage sags under load, which changes the VA proportionally.

For the reverse, use the VA to amps calculator. For the kilovolt-amp scale, see amps to kVA.

About the formula: Use the stated electrical relationship and enter values in the displayed units.

Frequently Asked Questions

How do I convert amps to VA?+

Multiply voltage by current, and by √3 for a three-phase circuit. VA = V × A × phase factor. A 10 A load on 120 V single-phase is 1,200 VA.

How is VA different from watts?+

VA is apparent power; watts is real power. VA is always equal to or greater than watts, and they're equal only for a purely resistive load. For a motor, transformer, or switch-mode supply, VA runs higher.

Why do UPS units and power strips list a VA rating?+

Because they have to carry the full current the load draws, whether or not that current does work. The VA figure — volts times amps — is what sizes their internal wiring, switches, and transfer relays.

Does entering the wrong voltage change the answer much?+

Proportionally. VA scales directly with voltage, so a 10 A load entered at 120 V gives 1,200 VA, and at 240 V gives 2,400 VA. Use the voltage the load actually runs on.

How do I get VA for a three-phase motor?+

Select three-phase, enter the line current and the line-to-line voltage, and the calculator applies the 1.732 factor. A 10 A three-phase load at 208 V is about 3,600 VA.

Is amps to VA the same as amps to kVA?+

Same calculation; kVA is just VA divided by 1,000. Use VA for small equipment and kVA for larger loads and panel work.