Size the buffer a connection needs given delay probability.
Risk depends on both how often the inbound is late and how large the buffer is relative to typical delays. The number of later flights matters as much, because it determines whether a misconnection costs hours or a night. A last flight of the day with a tight connection is the worst combination, since the failure mode is a hotel rather than a wait.
Flight Connection Buffer
Misconnect probability ≈ late probability × the share of delays exceeding the buffer
Misconnect probability ≈ late probability × the share of delays exceeding the buffer Risk depends on both how often the inbound is late and how large the buffer is relative to typical delays. The number of later flights matters as much, because it determines whether a misconnection costs hours or a night.
A last flight of the day with a tight connection is the worst combination, since the failure mode is a hotel rather than a wait.
This calculator takes 5 inputs: Scheduled connection, Minimum connection time, Inbound flight on-time performance, Average delay when late, Later flights available today. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.