Transformer VA Rating

How to use this calculator

A transformer's VA rating for a given winding is simply voltage times current: VA = V × I. Enter the winding voltage and the current it's expected to carry, and the VA rating appears live. For a complete transformer, take the larger of the primary and secondary VA values.

What it means in a real circuit

The VA rating is the thermal limit — how much apparent power the windings and core can carry before overheating. A 24 V winding rated at 5 A is a 120 VA transformer. You don't need the load's power factor to find the rating, only the voltage and current it must handle. Use this to verify a transformer is big enough for a given load before you commit to it, and to compare candidates on a common basis.