Blocking Factor is most commonly used in reference to technology access methods where a higher number of inputs are directed and re-directed to a smaller number of outputs. It is the ratio of Inputs to Outputs that determines the actual blocking factor. For instance, when 25 inputs are present requiring concurrent access to only 5 outputs, a blocking factor of "5" is said to exist. In essence, 1 request out of 5 can be handled.

In very practical applications, large numbers of users may be contending for access to a more limited number of physical devices as is the case for KVM Switches. For KVM applications, typical designs for blocking factors of 4 or 8 are very common.