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Minimum connection time (MCT) is not a universal rule but an airport-specific, industry-approved measure published by airport operators and enforced by airlines. The MCT is the shortest allowed interval between the scheduled arrival of an incoming flight and the scheduled departure of an onward connecting flight.
In this guide
What minimum connection time is
Who sets it
Why domestic and international connections differ
What minimum connection time is
The International Air Transport Association (IATA) defines the Station Standard Minimum Connecting Time (MCT) as "the standard airport official shortest time interval required to transfer a passenger and their luggage from one flight to a connecting flight" at a specific airport or metropolitan area. This means that if you book a connecting flight with a layover shorter than the MCT of your destination airport, you're block-booked; the airline will not schedule the flight.
The default MCTs based on transfer types are: 30 minutes for domestic-to-domestic, 60 minutes for domestic-to-international, 90 minutes for international-to-domestic, and 90 minutes for international-to-international connections. However, these default MCTs may be longer or shorter, depending on the individual airport.
Who sets it
Typically, an airport's operators agree on the MCT and then formally submit it to IATA for approval. After the approval process, the MCT becomes the default industry value for that airport. In case an airport hasn't published their specific times, IATA provides fallback MCT values.
So, to illustrate how the process works, an airport operator calculates what is a safe and feasible transfer time at their facility and submits that time to IATA. Once IATA approves the submitted times, the MCT becomes publicly available until it is updated.
Why domestic and international connections differ
IATA notes that domestic flights connecting to international flights, or vice versa, generally get a longer MCT. This discrepancy is usually because international transfers may need to pass through customs and immigration, which can add to the transfer time.
For instance, domestic-to-international connections often have longer MCTs than domestic-to-domestic ones at major airports.
Therefore, it's essential to know what types of connections you're booking and the approximate additional time it will take to land at your final destination.
What the published number does and does not tell you
As published value, the MCT is the minimum time an airline is willing to schedule for a layover, not a safety buffer or guarantee that you will comfortably reach your next flight. For example, if you need a wheelchair, walk with canes or crutches, or travel with children or pets, you may want to book a longer layover.
The MCT is also based on scheduled, not actual, flight times - that is, the value reflects when your incoming and outgoing flights are supposed to arrive and depart, not when they actually land and take off. The actual flight arrival and departure times may vary due to flight disruptions. Therefore, the MCT is a useful industry floor, not a passenger comfort assurance.
