This tool converts Voltage Standing Wave Ratio or **VSWR** to Reflection Coefficient (sometimes referred to as Gamma) **Γ**.

Reflection Coefficient Γ to VSWR

## Formula

**Γ = (VSWR – 1)/(VSWR + 1)**

**VSWR** is a positive number greater than or equal to **1**

## Background

**VSWR** (sometimes called standing-wave ratio SWR) is a measure of the impedance match between a feedline’s characteristic impedance and the attached load. The load can be an antenna or any RF module such as a filter or amplifier. The greater the degree of mismatch the less efficient the design and implementation.

VSWR is often expressed as a ratio to 1. For example, if the VSWR is **1.9** then it is written as **1.9:1**.

Within the context of antennas **a good value of VSWR is 1.5 or lower**. In an ideal situation, the load is perfectly matched to the feedline characteristic impedance, **VSWR=1** and using the calculator **Γ=0**. In this case, no signal energy is reflected and all of it is transmitted forward.