Single phase Amps to VA calculation formula
S(VA) = I(A) × V(V)
The apparent power S in volt-amps (VA) is equal to the phase current I in amps (A), multiplied by the RMS voltage V in volts (V).
So,
VA = A x V
volt-amps = amps x volts
For example:
Phase current (I) = 2,5A
Voltage (V) = 110V
Power (S) = 2,5A x 110V = 275VA
3 phase Amps to VA calculation formula
Line to line voltage
S(VA) = √3 × I(A) × VL-L(V)
The apparent power S in volt-amps (VA) is equal to square root of 3, multiplied by the phase current I in amps (A), multiplied by the line to line RMS voltage VL-L in volts (V).
So,
VA = √3 × A x V
volt-amps = √3 × amps x volts
For example:
Phase current (I) = 2,5A
Voltage (V) = 110V
Power (S) = √3 x 2,5A x 110V = 476,3VA
Line to neutral voltage
S(VA) = 3 × I(A) × VL-N(V)
The apparent power S in volt-amps (VA) is equal to 3, multiplied by the phase current I in amps (A), multiplied by the line to neutral RMS voltage VL-N in volts (V).
So,
VA = 3 × A x V
volt-amps = 3 × amps x volts
For example:
Phase current (I) = 2,5A
Voltage (V) = 110V
Power (S) = 3 x 2,5A x 110V = 825VA