Transformer Turns Ratio Calculator
Calculate transformer turns ratio and the voltage and current transformation it produces.
About Transformer Turns Ratio Calculator
Voltage scales with turns while current scales inversely, so power is conserved. Impedance transforms with the square of the ratio, which is the basis of impedance matching in both power and audio applications. The volts-per-turn figure is constant for both windings and is the first thing checked when rewinding or verifying a transformer.
Formula
Transformer Turns Ratio
V_p ÷ V_s = N_p ÷ N_s = I_s ÷ I_p; impedance scales with the square of the ratio
- turns ratio
- Ratio of primary to secondary turns
- impedance ratio
- Turns ratio squared, how impedance is transformed
Worked example
With the default values below, Transformer Turns Ratio Calculator returns Turns Ratio of 27.5000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Primary voltageminimum 0.01 V
- 11,000 V
- Secondary voltageminimum 0.01 V
- 400 V
- Primary turnsminimum 1
- 1,100
- Secondary currentminimum 0 A
- 500 A
Results
- Turns Ratio
- 27.5000
- Secondary Turns
- 40.0
- Primary Current
- 18.182 A
- Volts per Turn
- 10.0000 V
- Impedance Transformation Ratio
- 756.25
Step by step
- 1Values used
- 2Transformer Turns Ratio
- 3Turns Ratio= 27.5000
- 4Secondary Turns= 40.0
- 5Primary Current= 18.182 A
- 6Volts per Turn= 10.0000 V
- 7Impedance Transformation Ratio= 756.25
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Transformer Turns Ratio calculated?
V_p ÷ V_s = N_p ÷ N_s = I_s ÷ I_p; impedance scales with the square of the ratio Voltage scales with turns while current scales inversely, so power is conserved. Impedance transforms with the square of the ratio, which is the basis of impedance matching in both power and audio applications.
Why does Transformer Turns Ratio matter?
The volts-per-turn figure is constant for both windings and is the first thing checked when rewinding or verifying a transformer.
What values do I need to enter?
This calculator takes 4 inputs: Primary voltage, Secondary voltage, Primary turns, Secondary current. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.