Difference Between Bit Rate and Baud Rate

In digital communication, bit rate and baud rate are two important terms used to describe how fast data is transmitted. Although they appear similar, they represent different aspects of data transmission.

• Bit Rate → Measures how many bits are transmitted per second.
• Baud Rate → Measures how many symbols (signal changes) are transmitted per second.

If one symbol carries more than one bit, then:
→ Bit Rate > Baud Rate

Bit Rate

Bit rate refers to the number of bits transmitted per second and is, therefore, a measure of the rapidity at which data is being transmitted over a communication channel. It is normally expressed in Kbps, Mbps, or Gbps. It will, therefore, give the relative efficiency of computer processing or handling data.

Bit Rate = Baud Rate × No. of Bits per Baud

Units:

• Kbps (Kilobits per second)
• Mbps (Megabits per second)
• Gbps (Gigabits per second)

Example:

If each symbol carries 4 bits and the system sends 2000 symbols per second, then:

Bit Rate=2000×4=8000 bps\text{Bit Rate} = 2000 \times 4 = 8000 \text{ bps}Bit Rate=2000×4=8000 bps

Baud Rate

It is defined to be the number of signal changes or symbols sent per second over a communication channel. This decides the extent to which a transmission medium, such as a wire or a wireless spectrum, is capable of changing its state in one second. Every such change can represent one or more bits of data.

Units: Baud (symbols/second).

Baud Rate = Bit Rate / No. of Bits per Baud

Importance of Baud Rate:

• Determines how frequently the signal must change.
• Affects required bandwidth of the channel.
• Higher baud rate → more signal changes → more bandwidth needed.

Example:

If the bit rate is 12000 bps and each symbol carries 3 bits, then:

Baud Rate=120003=4000 baud\text{Baud Rate} = \frac{12000}{3} = 4000 \text{ baud}Baud Rate=312000​=4000 baud

Difference Between Bit Rate and Baud Rate