Transformer Size Calculator

Size a transformer (kVA) for single-phase or three-phase loads with a safety margin.

kW
PF
%
Result
kW
PF
%
Result

Formulas

  • kVA required = kW / PF
  • With margin: kVA_sized = kVA required × (1 + spare%/100)
  • Standard sizes: 1, 1.5, 2, 3, 5, 7.5, 10, 15, 25, 50, 75, 100, 167, 250, 333, 500 kVA