What is the difference between baud rate and bit rate?

Bits, as you probably know, are the 0’s and 1’s that binary data consists of. The bit rate is a measure of the number of bits that are transmitted per unit of time – where the unit of time can be anything. Generally you will see the bit rate measured in bits per second. This means that if a network is transmitting 15,000 bits ever second, the bit rate is 15,000 bps – where bps obviously stands for bits per second.
The baud rate, which is also known as symbol rate, measures the number of symbols that are transmitted per unit of time. A symbol typically consists of a fixed number of bits depending on what the symbol is defined as. The baud rate is measured in symbols per second.
The difference between baud rate and bit rate
To summarize, the bit rate measures the number of bits transmitted per second, whereas the baud rate measures the number of symbols transmitted per second – and that is the major difference between the two.
Can the baud rate equal the bit rate?
Because symbols are comprised of bits, the baud rate will equal the bit rate only when there is just one bit per symbol.