Frequency Converter

Type a frequency or a period in any common unit and get all the others at once. Frequency and period are reciprocals, so the tool normalises whatever you entered to hertz and then shows it in Hz, kHz, MHz and GHz, the matching period in seconds down to nanoseconds, the angular frequency ω = 2πf in radians per second, and the equivalent in revolutions per minute.

The reciprocal relationship is the reason a period is often the easier thing to reason about. A 2.4 GHz signal has a period of about 0.42 nanoseconds, which is roughly the time light takes to cross twelve centimetres — which is in turn why antennas for that band are a few centimetres long, and why a trace on a circuit board starts behaving like a transmission line at those speeds. Going the other way, a 50 Hz mains cycle is 20 milliseconds, which is why a camera shutter near that interval produces banding under old lighting.

Angular frequency is where a factor of 2π quietly enters and refuses to leave. It is the same physical rate expressed as radians swept per second rather than whole cycles per second, so 50 Hz is 314.16 rad/s. Filter equations, impedances and phase calculations are written in ω, and a formula transcribed from a textbook into code with f substituted for ω is off by 6.28 — a mistake that produces plausible-looking output rather than an error, which is why it survives review.

Revolutions per minute is the same quantity again with a different denominator: one hertz is sixty RPM, so a 7,200 RPM drive spins at 120 Hz. And a caveat about units that share a dimension without sharing a meaning. Hertz, becquerels and radians per second are all reciprocal seconds, and the SI keeps them apart by what is being counted rather than by the algebra. Bits per second is not hertz either, since a modulation scheme can carry several bits per symbol — a distinction that matters the moment someone quotes a baud rate as though it were a bandwidth.