🔌 Impedance Matching Calculator
Check how well two impedances are matched by calculating the reflection coefficient, VSWR, and return loss.
1
ohm
2
ohm
Why Impedance Matching Matters
When a signal source and its load have different impedances, some of the signal’s energy reflects back toward the source instead of being delivered to the load. This wastes power and can cause signal distortion, especially in RF, antenna, and transmission-line systems.
The Formulas
The reflection coefficient is Γ = (ZL – Z0) ÷ (ZL + Z0). From it, the Voltage Standing Wave Ratio is VSWR = (1 + |Γ|) ÷ (1 – |Γ|), and return loss is -20 × log10(|Γ|) in decibels.
- A VSWR of 1:1 (or Γ = 0) means a perfect match with no reflected power.
- Higher VSWR and lower return loss both indicate a worse mismatch.
- This tool covers the standard RF/electronics reflection formulas and is intended for general engineering reference and education.
Last reviewed August 2026