VSWR Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserIntermediate
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the forward and reflected power in watts.
- Read VSWR, return loss and reflection coefficient.
How it works
Reflection coefficient Γ = √(reflected ÷ forward); VSWR = (1 + Γ) ÷ (1 − Γ); return loss = −10·log10(reflected ÷ forward).
Worked example
100 W forward, 5 W reflected. VSWR ≈ 1.58:1, return loss ≈ 13 dB.
Common mistakes
- Reflected power can't exceed forward power.
- Confusing a high VSWR (bad match) with high power.
Frequently asked questions
What VSWR is acceptable?
1:1 is perfect; under about 1.5:1 is generally good, and many rigs fold back power above ~2:1 or 3:1.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.