In telecommunications and electronics, baud (pronounced ) is a measure of the "signaling rate" which is the number of changes to the transmission media per second in a modulated signal. It is named after Émile Baudot, the inventor of the Baudot code for telegraphy.

The term baud is sometimes misused to refer to "bits per second" which is the "data rate". In some systems the signaling rate and the data rate are the same since it is possible for one signalling event to carry one bit, but in general it is more common to make more efficient use of bandwidth by encoding multiple bits—as many as sixteen—in one event. Thus, a 2400-bit/s modem actually transmits at 600 baud, where each quadrature amplitude modulation event carries four bits of information.

See also

• Modem
• Bandwidth
• List of device bandwidths