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Turns Ratio Calculator

Calculate a transformer's turns ratio from primary and secondary voltage (a = Vp ÷ Vs).

Formula

a = Vp ÷ Vs

a
Turns ratio
Vp
Primary voltage, in volts
Vs
Secondary voltage, in volts

What this calculator does

Calculates a transformer's turns ratio from its primary and secondary voltage.

Use cases

  • Check a transformer's rated turns ratio against measured voltages
  • Find the expected secondary voltage for a known primary voltage and ratio
  • Compare step-up vs. step-down transformer specifications