Amps to VA Calculator

Amps to VA calculation

How do you convert amps to VA for single phase?

The apparent power S in volt-amps (VA) is equal to the current I in amps (A), times the voltage V in volts (V): S(VA) = I(A) × V(V). For example, a 5 A load on a 120 V supply is 5 × 120 = 600 VA.

How do you convert amps to VA for three phase?

The apparent power S in volt-amps is equal to the square root of 3, times the current I in amps, times the line-to-line voltage VL-L in volts: S(VA) = √3 × I(A) × VL-L(V). For example, 10 A at 480 V line-to-line gives √3 × 10 × 480 ≈ 8313.84 VA. Using line-to-neutral voltage instead, the equivalent form is S(VA) = 3 × I(A) × VL-N(V).

What is the difference between VA and watts?

VA measures apparent power — volts times amps as they are drawn — while watts measure real power actually consumed. On a resistive load they match; on motor- or electronics-type loads the real power is lower by the power factor (W = VA × PF). This calculator gives apparent power only.

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). For three phase the √3 factor is applied automatically.

Worked example

A three-phase motor drawing 1 A on a 208 V line-to-line supply needs S = √3 × 1 A × 208 V ≈ 360.27 VA of apparent power. The same current at the same voltage on single phase would be 1 A × 208 V = 208 VA.