This calculator helps you determine the impedance transformation ratio of a **balun** (balanced to unbalanced) or **unun** (unbalanced to unbalanced) based on the turns ratio of the transformer windings.

The formula used is: \[ \text{Impedance Ratio} = \left( \frac{N_{\text{secondary}}}{N_{\text{primary}}} \right)^2 \] Where:

• N_primary = number of turns on the input side
• N_secondary = number of turns on the output side

If you input a known impedance on either the primary or secondary side, the calculator will also show the matched impedance on the other side. For example, a 4:1 balun (2:1 turns ratio) will match 50 Ω to 200 Ω.

Common ratios:

• 1:1 → no transformation
• 2:1 → 4:1 impedance transformation
• 3:1 → 9:1 transformation (e.g. for end-fed halfwaves)