Flight Connection Buffer Calculator

Size the buffer a connection needs given delay probability.

About Flight Connection Buffer Calculator

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.

Formula

Flight Connection Buffer

Misconnect probability ≈ late probability × the share of delays exceeding the buffer

buffer: Connection time above the published minimum
recovery option: A later flight that day on the same route

Worked example

With the default values below, Flight Connection Buffer Calculator returns Buffer Above the Minimum of 45. Change any input above and every figure here is recalculated in your browser.

Inputs used

Scheduled connectionminimum 0 min: 120 min
Minimum connection timeminimum 0 min: 75 min
Inbound flight on-time performanceaccepts 0–100 %: 78 %
Average delay when lateminimum 0 min: 35 min
Later flights available todayminimum 0: 3

Results

Buffer Above the Minimum: 45 min
Probability of Misconnecting: 7.86%
Delay the Buffer Absorbs: 45 min
Recovery Options if Misconnected: 3
Recommendation: Moderate risk, but recovery options exist

Step by step

1Values used
2Flight Connection Buffer
3Buffer Above the Minimum= 45 min
4Probability of Misconnecting= 7.86
5Delay the Buffer Absorbs= 45 min
6Recovery Options if Misconnected= 3
7Recommendation= Moderate risk, but recovery options exist

Assumptions and limits

The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Flight Connection Buffer calculated?

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.

Why does Flight Connection Buffer matter?

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.

What values do I need to enter?

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.