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Electrical Engineering Calculators

Transformer Ratio Calculator

Turns ratio, secondary current and VA rating for a step-up or step-down transformer.

Enter values

Results update as you type.

Result

Turns ratio

19.167 : 1

Type
Step-down
Secondary VA
60 VA
Primary current
0.2746 A
Losses
3.16 W

About the Transformer Ratio Calculator

Turns ratio, secondary current and VA rating for a step-up or step-down transformer.

Also known as: turns ratio, step up transformer, step down transformer, transformer calculator.

How to use this calculator

  1. Enter primary voltage, secondary voltage, primary turns (optional), secondary current and the other fields.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

Vp / Vs = Np / Ns = Is / Ip

Worked example

Using the values pre-filled in the calculator above:

  • Primary voltage = 230 V
  • Secondary voltage = 12 V
  • Primary turns (optional) = 0
  • Secondary current = 5 A
  • Efficiency = 95 %

the calculator returns:

  • Turns ratio: 19.167 : 1
  • Type: Step-down
  • Secondary VA: 60 VA
  • Primary current: 0.2746 A