SWR calculator
SWR and reflection coefficient dual modes
Convert SWR, reflection coefficient and return loss from forward/reflected power or complex impedance using math.js for precise parsing.
Results SWR calculator
SWR 1.58
Return loss
13.0 dB
SWR = (1 + √(Pr/Pf)) / (1 - √(Pr/Pf)), valid only when Pr < Pf.
SWR itself does not kill transmit power, but the reflected wave forces the amplifier and feedline to work harder. Check the additional attenuation with the Coax Loss Calculator—even a few dB makes a big difference at UHF.
When the feedpoint impedance is nowhere near 50Ω, model a simple network in the Matching Network Designer. A quick L-match or series stub often restores a low SWR without retuning the antenna immediately.