Return Loss is a measure of the amount of energy that is reflected back at a discontinuity in a Radio Frequency Circuit [1]. It is specified in **dB**.

This calculator converts Return loss (RL) to Voltage Standing Wave Ratio (VSWR).

**Formula**

**VSWR = (1 + 10 ^{-RL/20})/(1 – 10^{-RL/20})**

**Example Calculation**

A Return Loss of **10 dB** is equivalent to a VSWR of **1.93**.

Note that like Return Loss, VSWR has no units. It is often written as a ratio relative to 1. For example, **VSWR = 1.93:1**

**What is Return Loss?**

Return loss is the ratio between the incident and reflected energy at the input of an RF system. Mathematically it is represented as

**Return Loss = Incident Power / Reflected Power**

In a good design, no power is reflected back. However in actual practice, there’s always some power that is returned back to the source on account of impedance mismatch.

A good design goal is to aim for a return loss of **at least **14 dB across the specified frequency range. In general return loss should be as high as possible.

**References**

[1] Return Loss