VSWR / Return Loss Calculator

Bidirectional conversion between VSWR, return loss, reflection coefficient, and mismatch loss.

What is VSWR?

Push a child on a swing at the wrong moment and energy bounces back to your hands. VSWR (Voltage Standing Wave Ratio) measures how much signal bounces back from a mismatched antenna — 1:1 is perfect, higher numbers mean more wasted energy.

Why does this matter?

Ham radio operators check VSWR before transmitting to protect their equipment. Reflected power heats up the transmitter and wastes energy. A VSWR above 3:1 can damage some radios.

Input Parameter
Select which parameter you know and enter its value.

Voltage Standing Wave Ratio. 1.0 = perfect match (nothing bounces back), ∞ = total reflection (everything bounces back).

Quick presets (VSWR):

Converted Values
VSWR2.00:1
Acceptable
Reflection Coefficient |Γ|
0.3333
Return Loss
9.54 dB
Mismatch Loss
0.512 dB
Power Transmitted
88.89 %
Power Reflected
11.11 %

A VSWR of 2:1 or better (return loss ≥ 9.54 dB) is generally acceptable for most RF applications. Transmitters may be damaged by high VSWR due to reflected power.