Propagation Delay Calculator
Enter the distance a signal travels and the cable’s velocity factor to calculate the propagation delay.
What this calculator does
Propagation delay is the time it takes an electrical or optical signal to travel down a cable or transmission line from one end to the other, which matters for network latency and timing budgets.
How the calculation works
The signal’s effective speed equals the speed of light in a vacuum multiplied by the cable’s velocity factor (a value less than 1, since signals travel slower in copper or fiber than in a vacuum). Propagation delay then equals distance divided by that effective speed: delay = distance ÷ (c × velocity factor).
Typical velocity factors are about 0.6-0.7 for copper cabling and around 0.66-0.7 for common fiber optics; check your specific cable’s datasheet for an exact value.