Using the VSWR Calculator

The VSWR / Return Loss Calculator converts between voltage standing-wave ratio (VSWR), return loss, reflection coefficient magnitude (|Γ|), and percent return. The conversions are mathematical; interpreting a measurement still depends on the calibrated setup and reference plane.

Enter a value

Choose the quantity you know and enter one value. VSWR must be at least 1.0; 1.0 represents a perfect match in the idealized calculation. Set the decimal precision to control how results are displayed. Use Formulas to see the relationships behind the conversions.

Optional power and sweep results

If useful, enter incident power in watts or dBm to see the corresponding reflected-power estimate. Review the results and sweep table together; displayed precision is not measurement accuracy. Copy Results to use the calculated values elsewhere, and Reset to start over.

Limits: This tool does not measure a device or correct for calibration, cable loss, adapters, or reference-plane errors. Compare values only when the measurement setup and reference plane are understood. Use a calibrated instrument for acceptance measurements.