Return Loss ↔ VSWR Calculator

Type either Return Loss (dB) or VSWR, then click Calculate. The tool also shows the reflection coefficient magnitude (|Γ|), reflected power %, delivered power %, and mismatch loss.

Inputs

Return Loss (dB)

VSWR

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Valid ranges: RL ≥ 0 dB, VSWR ≥ 1. Uses magnitudes only (|Γ|).

Key Metrics

|Γ| (magnitude)

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Reflected Power

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Delivered Power

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Mismatch Loss

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Formulas:

VSWR = (1 + |Γ|)/(1 − |Γ|)

RL(dB) = −20·log₁₀|Γ|

|Γ| = 10^(−RL/20) = (VSWR − 1)/(VSWR + 1)

% Reflected Power = |Γ|² × 100

% Delivered Power = (1 − |Γ|²) × 100

Mismatch Loss (dB) = −10·log₁₀(1 − |Γ|²)

Reference Table

Common points from good to poor match.

RL (dB)	VSWR	\|Γ\|	Reflected %	Mismatch Loss (dB)
Good anchors: 14 dB ≈ 1.5:1 · 20 dB ≈ 1.22:1 · 26 dB ≈ 1.1:1

Engineering notes: Lower VSWR and higher RL indicate better matching, lower reflections, and higher power transfer. In practical RF systems, RL ≥ 20 dB (VSWR ≲ 1.22:1) is often a good target; constraints vary by band and application.

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