Transformer Voltage Ratio Calculator

Use this simple transformer ratio workflow for ideal voltage-ratio checks. It does not evaluate taps, regulation, impedance, or winding configuration.

  • Updated August 22, 2026
Inputs
Result

Formulas

  • Voltage ratio = primary voltage / secondary voltage
  • Secondary per primary volt = secondary voltage / primary voltage

Use this calculator

Estimate transformer voltage ratio from primary and secondary voltages.

Read the result

Review the calculated values with their displayed units and assumptions. The result is a planning aid for the stated inputs, not a final equipment or installation decision.

Check before final work

This transformer ratio estimate uses ideal voltage ratio only. It does not evaluate taps, regulation, impedance, connection type, or equipment approval.

FAQs

Is this the same as turns ratio?

For an ideal transformer, the voltage ratio follows the turns ratio. Real equipment can also involve taps, regulation, winding connections, and manufacturer data.

Does this include transformer voltage regulation?

No. It is an ideal ratio check only and does not model loaded voltage drop or regulation.