VA to Amps Calculator

VA to amps calculation

How do you convert VA to amps for single phase?

The current I in amps (A) is equal to the apparent power S in volt-amps (VA), divided by the voltage V in volts (V): I(A) = S(VA) / V(V). For example, a 1200 VA load on a 120 V supply draws 1200 / 120 = 10 A.

How do you convert VA to amps for three phase?

The current I in amps is equal to the apparent power S in volt-amps, divided by the square root of 3 times the line-to-line voltage VL-L in volts: I(A) = S(VA) / (√3 × VL-L(V)). For example, 10000 VA on a 400 V line-to-line supply gives 10000 / (√3 × 400) ≈ 14.434 A. Using line-to-neutral voltage instead, the equivalent form is I(A) = S(VA) / (3 × VL-N(V)).

Why is the three-phase current lower than single phase for the same VA and volts?

A three-phase system delivers power over three conductors, so each conductor carries only 1/√3 (about 58%) of the current the same apparent power would draw from a single-phase supply at the same voltage. The calculator applies the √3 divisor automatically when you pick "Three phase".

Which voltage goes in the volts field?

Always the line-to-line voltage: the supply voltage measured between conductors (120 V or 230 V mains for single phase, 208 V, 400 V or 480 V for typical three-phase systems).

Worked example

A 5000 VA three-phase load on a 208 V line-to-line supply draws I = 5000 / (√3 × 208) ≈ 13.879 A. The same 5000 VA on a single-phase 208 V supply would draw 5000 / 208 ≈ 24.038 A. Note VA to amps needs only VA and volts; converting from watts instead requires the power factor.