Baud Rate Calculator Formula

Understand the math behind the baud rate calculator. Each variable explained with a worked example.

Use the Baud Rate Calculator

Formulas Used

Gross Bit Rate

gross_bit_rate = baud_rate * bits_per_symbol

Effective Data Rate

effective_throughput = baud_rate * bits_per_symbol * data_bits_per_frame / (data_bits_per_frame + start_stop_bits)

Protocol Efficiency

efficiency_pct = data_bits_per_frame / (data_bits_per_frame + start_stop_bits) * 100

Variables

VariableDescriptionDefault
baud_rateBaud Rate (symbols/s)(Bd)9600
bits_per_symbolBits per Symbol(bits)1
start_stop_bitsOverhead Bits per Frame(bits)2
data_bits_per_frameData Bits per Frame(bits)8

How It Works

Baud Rate vs Bit Rate

Formulas

Bit Rate = Baud Rate x Bits per Symbol

Throughput = Bit Rate x Data Bits / (Data + Overhead Bits)

UART at 9600 baud with 8N1 framing: 9600 bps gross, 7680 bps effective (80% efficient due to start/stop bits).

Worked Example

UART at 9600 baud, 1 bit/symbol, 8 data bits, 2 overhead bits (start + stop).

baud_rate = 9600bits_per_symbol = 1start_stop_bits = 2data_bits_per_frame = 8
  1. 01Gross bit rate = 9600 x 1 = 9600 bps
  2. 02Effective = 9600 x 8 / 10 = 7680 bps
  3. 03Efficiency = 8 / 10 = 80%

Ready to run the numbers?

Open Baud Rate Calculator