Transformer Turns Ratio Calculator
Calculate ideal voltage, turns, and current relationships from primary and secondary winding values.
Enter transformer values
Ideal winding relationships
About this calculator
Calculate ideal voltage, turns, and current relationships from primary and secondary winding values.
The ideal model ignores losses, magnetizing current, regulation, winding connections, and nameplate tolerances. Enter actual winding values rather than assuming a line-voltage ratio.
Method and assumptions
For an ideal transformer, primary-to-secondary voltage ratio equals turns ratio. Secondary turns = primary turns ÷ ratio; secondary current = primary current × ratio. These are winding quantities, not automatically three-phase line quantities.
Ideal ratio and capacity arithmetic do not include winding losses, temperature rise, harmonics, load diversity, or equipment-specific limits unless stated in the input model.
FAQs
Does this determine a complete transformer installation?
No. It performs the displayed arithmetic only. Verify the transformer nameplate, manufacturer application data, connections, protection, conductors, and locally adopted requirements separately.
Can I use line-to-line voltage as winding voltage for every three-phase transformer?
No. Use the actual winding voltage or turns data. Three-phase line-voltage ratios depend on winding connections and are not always equal to individual winding turns ratios.
Sources
Ideal transformer relationships, entered nameplate and test values, and the calculation conventions described above.