Routing & planning
Minimum connection time
The shortest gap an airport says it can handle between two flights. Where the number comes from, what it assumes about you, and why it is a floor rather than a recommendation.
Published 9 September 2026 · Updated 9 September 2026
Minimum connection time — MCT in the industry, sometimes “minimum transfer time” — is the shortest gap an airport says it can move a passenger and their bags between two specific flights.
It is a real, published figure, filed by each airport and used by booking systems to decide which connections they are allowed to sell. If a routing appears on a booking site as a single ticket, it clears the MCT by definition. The system will not construct one that does not.
That makes it useful and widely misunderstood, because it is a floor, not a recommendation.
The number is not one number
An airport does not have “an” MCT. It files a matrix, and the figure that applies to you depends on what your connection actually involves:
| Connection type | Typical range |
|---|---|
| Domestic to domestic, same terminal | 30–45 min |
| Domestic to international | 60–90 min |
| International to domestic (with immigration) | 90–120 min |
| International to international, same terminal | 45–90 min |
| International to international, changing terminal | 90 min or more |
Large hubs file different figures for different terminal pairs, and sometimes for specific airline pairs, because two carriers in the same alliance may share facilities that others do not. Heathrow filing one number for a Terminal 5 to Terminal 5 connection and quite another for Terminal 5 to Terminal 2 is normal — the second involves a train.
What the number assumes about you
This is where it goes wrong. The MCT assumes:
- Both flights are on one ticket, with your bags checked through
- Everything runs on time
- You know where you are going and start walking immediately
- You need no assistance and are not travelling with small children
- Nothing unusual happens at immigration or security
Every one of those is an assumption about a good day. The figure is what the airport can do when things work — which is the right basis for a rule that decides what may be sold, and the wrong basis for deciding what you should buy.
When it does not apply at all
Separate tickets. If you booked two tickets, the MCT is irrelevant to you: it describes a protected connection with bags checked through, and you have neither. You need considerably more — see what is a self-transfer flight.
Different airports. No MCT covers Heathrow to Gatwick, or Suvarnabhumi to Don Mueang. That is a ground journey you plan yourself.
Where you intend to leave the airport. A different calculation entirely; see can you leave the airport during a layover.
How much margin to add
For a connection you are choosing rather than accepting:
- Domestic, same terminal, hand baggage only — the published minimum is genuinely fine
- Anything international — an hour over the minimum
- Terminal change, or immigration in the middle — 90 minutes over
- Last flight of the day onward — as much as you can get, because the cost of missing it is a night, not an hour
- Winter, or a hub with known weather exposure — more again
Chicago O’Hare is the standard example of the last point: enough US domestic traffic routes through it that its weather disrupts schedules nationally, and a tight connection there in January is a different proposition from the same connection in June.
What protects you if it fails
This is the part worth being clear about, because it is the actual reason a legal connection is worth paying for.
On one ticket, missing a connection because the first flight was late is the airline’s problem. They rebook you on the next available service, and where the delay is within their control, duty-of-care obligations may cover meals and a hotel. You are inconvenienced, not stranded.
On separate tickets, the second airline has no obligation whatsoever. Your ticket is a no-show and most fares forfeit it.
So the question is not really “is this connection legal?” — the booking system answered that. It is “if this goes wrong, who fixes it?”
Checking your own connection
Read both times exactly as printed on the itinerary. They are local to their own airports, so the gap between them is arithmetic you can do directly — but only if you resist converting anything, and only if you have noticed whether the arrival date differs from the departure date.
For a trip with several connections, the multi-city trip planner computes each leg’s arrival in local time and flags date changes, so a gap that looks like four hours is not secretly forty minutes.
Then check what the connection actually requires. The airport code lookup will tell you whether your two flights are even at the same airport — which, for cities with several, is not a given.
Related reading
- Layover vs stopover vs connection — the guide this supports
- What is a self-transfer flight? — when the MCT does not apply
- Flight itinerary guide — reading connection times correctly