VSWR Calculator
Voltage Standing Wave Ratio Calculator
Calculate VSWR from Return Loss, Reflection Coefficient,
or SWR instantly. Essential tool for RF engineers,
antenna systems, transmission lines, and wireless networks.
Accurate Results
Instant Calculation
RF & Antenna Ready
Engineering Grade
VSWR Formula
VSWR =
½
Vmax
Vmin
VSWR =
Vmax / Vmin
VSWR from Return Loss
VSWR from Reflection Coefficient
Return Loss from VSWR
Reflection Coefficient from VSWR
Enter Return Loss
dB
⇄
Return Loss (dB)
14.00
dB
Reflection Coefficient (|Γ|)
0.200
Mismatch Loss (dB)
0.18
dB
SWR (VSWR)
1.50
Formulas Used:
Return Loss = −20 log₁₀(|Γ|)
VSWR = (1 + |Γ|) / (1 − |Γ|)
Mismatch Loss = −10 log₁₀(1 − |Γ|²)
Tips:
Lower VSWR values indicate better impedance matching.
Ideal VSWR is 1:1 (perfect match).
1.0 – 1.5 : 1
Excellent
1.5 – 2.0 : 1
Good
2.0 – 3.0 : 1
Acceptable
> 3.0 : 1
Poor
📡
Quick Reference (VSWR Guide)
| VSWR | Return Loss (dB) |
Reflection Coefficient (|Γ|) |
Mismatch Loss (dB) |
|---|---|---|---|
| 1.1 | 26.44 | 0.0476 | 0.01 |
| 1.2 | 20.83 | 0.0909 | 0.04 |
| 1.5 | 14.01 | 0.2000 | 0.18 |
| 2.0 | 9.54 | 0.3333 | 0.51 |
| 3.0 | 6.02 | 0.5000 | 1.25 |
| 5.0 | 4.44 | 0.6667 | 2.09 |
| 10.0 | 2.45 | 0.8182 | 3.58 |
What is VSWR?
VSWR (Voltage Standing Wave Ratio) is a measure of how efficiently
radio-frequency power is transmitted from a power source,
through a transmission line, into a load.
VSWR of 1:1 is ideal (perfect match)
Lower VSWR indicates better impedance matching
Higher VSWR indicates more signal reflection
Common in antennas, transmission lines, and RF systems
Keep VSWR below 2:1 for most applications
Frequently Asked Questions
VSWR (Voltage Standing Wave Ratio) measures how efficiently RF power is transmitted from a source to a load.
A VSWR close to 1:1 is ideal. Values below 1.5:1 are generally considered excellent.
High VSWR is caused by impedance mismatch, poor connectors, damaged cables, or antenna tuning issues.
Return loss measures the amount of RF power reflected back because of impedance mismatch.
Yes. Excessive reflected power can overheat and damage RF transmitters and amplifiers.
Proper impedance matching improves signal transfer efficiency and reduces reflected power losses.
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