Enter the volume of the vessel, the change in pressure, and the change in time into the calculator to determine the vacuum leak rate.

Vacuum Leak Rate Formula

The following equation is used to calculate the Vacuum Leak Rate.

L = -V * ΔP / ΔT
  • Where L is the leak rate (Pa * m^3/s)
  • V is the volume (m^3)
  • ΔP is the change in pressure (Pa)
  • ΔT is the change in time (s)

To calculate a leak rate, multiply the volume of the vacuum by the change in pressure over the changer in time.

What is a Vacuum Leak Rate?


Vacuum leak rate is sometimes referred to as a “leakage rate.” This term can be confusing at first because in most systems, leaks are not good things. However, when discussing vacuum systems, the word “rate” takes on a different meaning. It refers to how quickly pressure will increase inside the chamber if there are leaks in the piping or tubing that make up the vacuum system.

The more leaks there are and the larger they are, the faster pressure will rise inside the chamber. The vacuum leak rate is used by engineers to determine how long it will take for pressure to increase inside a given chamber after it has been pumped down.

This value is particularly important when designing high-vacuum chambers that require pumps capable of reaching pressures far lower than atmospheric pressure (the current record low vacuum is 10^-11 Torr).

Pumps capable of producing extreme vacuums need to be able to hold back increasing amounts of atmospheric pressure over time as they continue pumping down. If they do not have sufficient vacuum leak rate,