Transformer Calculator.

Calculate the primary and secondary full-load currents of the transformer. 
App also determines the turns ratio and type of transformer.

Select the number of phases ( 1Φ  or 3Φ )
Enter the transformer rating and select the appropriate VA / kVA
Enter the primary and secondary transformer voltages

and you get 
Primary full-load currents
Secondary full-load currents 
Turns Ratio = N1 / N2 = V1 / V2 = I2 / I1