What reading on an SWR meter indicates a perfect impedance match between the antenna and the feed line?

Standing Wave Ratio (SWR) is a mathematical ratio representing how well an antenna's impedance matches the feed line and transmitter. It compares the maximum and minimum voltage along the transmission line. When there is a perfect impedance match, all of the transmitter's power is transferred into the antenna and absolutely none is reflected back toward the radio. In this ideal scenario, the calculated ratio bottoms out at a baseline SWR reading of exactly 1:1. Because SWR is a ratio (specifically of 1 part forward power to 1 part accepted power), an SWR reading can never mathematically be lower than 1:1. Higher readings, such as 2:1 or 3:1, indicate increasing amounts of reflected power and a poorer impedance match.