Minimum connection time (MCT) is the shortest layover an airline is allowed to sell you at a particular airport. It is a rule for booking systems, not a promise that you will make it. Understanding it helps you choose a layover before you book, and judge your chances on the day.
What it is
Every airport has published minimum connection times, which airlines and booking systems use to decide which connections they can sell on a single ticket. A connection shorter than the MCT will not normally be offered. There is not just one number per airport. It varies with:
- Domestic or international. Connections involving an international flight usually need longer, especially arrivals into the US, because of passport control, customs and re-checking bags.
- Terminals. Changing terminals takes longer than staying in one.
- Airlines. A connection between two flights on the same airline is often allowed to be shorter than one between different airlines.
What it assumes
The MCT is the time a typical passenger needs if everything goes to plan: the first flight arrives on time at its scheduled gate, you get off promptly, and you walk directly to the next gate. It does not include:
- a late arrival, or a long taxi to a gate that is not ready
- a slow walk off the aircraft from the back rows
- a train between terminals, a long walk, or a security re-check
- the onward flight's boarding door closing before its departure time
That is why a connection can be perfectly legal and still very risky. Treat the MCT as a floor, not a target.
Who protects you if you miss it
When your airline sells you a connection at or above the MCT on one ticket, it takes responsibility for getting you to your destination if you miss it because of a delay. It rebooks you at no charge. See what happens if you miss a connecting flight.
Booking sites that combine separate tickets do not have to respect the MCT at all, and nobody is responsible for the connection except you. See missed connection on separate tickets.
Using it when you book
Choose a layover with comfortable room above the minimum, not one that just clears it. Our layover guide gives starting points for different kinds of connection, and the situations where you should allow more, such as winter at northern hubs or an onward flight that is the last of the day.
Using it on the day
When your first flight is delayed, the MCT is how you work out your real margin: take the revised arrival time, add the MCT, and compare the result with your onward departure. Whatever is left is your buffer. If it is close to zero, ask to be moved to a later connection before it is too late. See tight layover: how to tell if you will make it.
Airlines do not usually display the MCT to passengers. LateGate's Connection Assist uses the minimum connection time for your layover airport to show your real chance of making the connection as your first flight's timing changes.
This guide is general information for US travelers, not legal advice. Rules and airline commitments change; check with your airline or the US Department of Transportation for your specific situation.