how to calculate/find the rating of transformer in kva (single phase and three phase)?

To calculate the rating of a transformer in kVA, you can use the formula:
For single-phase transformers, the formula is:
[ text{kVA} = frac{V times I}{1000} ]
where ( V ) is the voltage in volts and ( I ) is the current in amperes.
For three-phase transformers, the formula is:
[ text{kVA} = frac{sqrt{3} times V times I}{1000} ]
where ( V ) is the line-to-line voltage. This calculation helps determine the transformer’s capacity to handle electrical loads.