Calculate VSWR
Choose your known values to calculate VSWR, reflection coefficient, return loss and other related metrics. The results will update automatically.
Results
VSWR
1.22 : 1
Excellent
Return Loss
20.08 dB
Mismatch Loss
0.04 dB
Reflected Power
0.99%
Reflection Coeff. (Γ)
0.10
VSWR to Return Loss Visualization
This chart visualizes the relationship between VSWR and Return Loss, acting as a real-time conversion tool. Your current result is highlighted on the chart. A lower VSWR corresponds to a higher Return Loss, indicating a better impedance match.
The Fundamentals of VSWR
Learn the core concepts behind VSWR, why it's a critical parameter in RF engineering, and the formulas used to calculate it.
What is Voltage Standing Wave Ratio (VSWR)?
VSWR is a measure of how efficiently radio-frequency power is transmitted from a power source, through a transmission line, into a load (for example, from a power amplifier, through a coaxial cable, to an antenna). It is the most common way to express the “impedance mismatch", which is directly related to "Return Loss" and "Reflection Coefficient".
In an ideal system, 100% of the power is transmitted. In a real system, however, some power is reflected back towards the source due to impedance mismatches. These forward and reflected waves interfere with each other, creating standing waves of voltage along the transmission line.
VSWR is the ratio of the maximum voltage to the minimum voltage along this line. A VSWR of 1:1 indicates a perfect impedance match with no reflected power. Higher VSWR values indicate a greater mismatch and more power being reflected.
VSWR Reference Chart
A quick lookup table for common VSWR values and their corresponding Return Loss and percentage of Reflected Power.
| VSWR | Return Loss (dB) | Reflected Power (%) | Performance |
|---|---|---|---|
| 1.0:1 | Infinity | 0% | Perfect |
| 1.1:1 | 26.44 | 0.23% | Excellent |
| 1.2:1 | 20.83 | 0.83% | Excellent |
| 1.3:1 | 17.69 | 1.7% | Very Good |
| 1.5:1 | 13.98 | 4.0% | Good |
| 1.7:1 | 11.73 | 6.7% | Acceptable |
| 2.0:1 | 9.54 | 11.1% | Fair |
| 3.0:1 | 6.02 | 25.0% | Poor |
| 5.0:1 | 3.52 | 44.4% | Very Poor |
