What is a good VSWR value?

A VSWR of 1.0 is perfect (no reflection). Values below 1.5 are generally considered excellent for most RF applications. Values above 3.0 indicate significant mismatch and potential power loss or component stress.

What is the reflection coefficient (Gamma)?

Gamma (Γ) is the ratio of the reflected wave amplitude to the incident wave amplitude. It ranges from 0 (perfect match) to 1 (total reflection). It relates to VSWR as: Gamma = (VSWR - 1) / (VSWR + 1).

How is return loss different from mismatch loss?

Return loss measures how much power is reflected (higher dB = better match). Mismatch loss measures how much incident power is lost due to the mismatch (i.e., not delivered to the load). Both are expressed in dB.

Can I enter complex impedances?

This calculator uses the magnitudes of the impedances. For complex (reactive) loads, use the magnitude |Z| = sqrt(R² + X²) and enter that value. Full complex VSWR analysis requires a Smith chart tool.

What does the reflected power percentage mean?

It is the fraction of the incident power that is reflected back toward the source, equal to |Gamma|² × 100%. The remaining percentage is the power actually delivered to the load.

VSWR Calculator

Calculate VSWR, return loss, mismatch loss, and reflected power from reflection coefficient or source/load impedances.

Input Mode

Reflection Coefficient |Γ|

Enter a value between 0 and 1 (exclusive).

Common Reference Values

Perfect match VSWR = 1.00 |Γ| = 0.000

Excellent (<1.5) RL > 14 dB

Good (<2.0) RL > 9.5 dB

Poor (>3.0) RL < 6.0 dB

Enter values and click Calculate to see results.

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Summary

The VSWR (Voltage Standing Wave Ratio) Calculator computes key RF transmission-line metrics from either a reflection coefficient (Gamma) or a source/load impedance pair. Enter your values and instantly see VSWR, return loss in dB, mismatch loss in dB, and the percentage of power reflected back toward the source. All calculations follow standard transmission-line theory and are performed entirely in your browser.

How it works

Choose your input mode: reflection coefficient (Gamma) or impedance (Z0 and ZL).
Enter the required values in the input fields.
The calculator derives the reflection coefficient if you used the impedance mode.
VSWR is computed as (1 + |Gamma|) / (1 - |Gamma|).
Return loss, mismatch loss, and reflected power are derived from VSWR and Gamma.
Results update instantly as you type.

Use cases

Evaluate antenna impedance matching quality.
Verify RF transmission-line performance during design.
Convert between VSWR, return loss, and reflection coefficient.
Assess reflected power in amplifier output stages.
Diagnose coaxial cable or connector faults in RF systems.
Calculate mismatch loss in microwave circuits.
Check feed-line efficiency for amateur radio installations.
Validate VNA measurement results.

Frequently Asked Questions

Last updated: 2026-05-29 · Reviewed by Nham Vu

VSWR Calculator

Use the VSWR Calculator

Summary

How it works

Use cases

Frequently Asked Questions