At Amsterdam Schiphol (AMS), a 55-minute layover is legally "sufficient" but can be very tight in practice. KLM and the airport officially recommend a minimum connection time (MCT) of 40 minutes for Schengen-to-Schengen flights and 50 minutes for non-Schengen international connections. Because Schiphol is a "one-terminal" concept, you don't need to change buildings, which saves time. However, the airport is massive, and walking from a "B" gate to an "E" gate can easily take 20 minutes. If you are arriving from outside the EU (e.g., from the US or UK) and connecting to a European destination, you must pass through Passport Control, which can have long queues in 2026. If your first flight is even 15 minutes late, you risk missing your connection. If your flights are on a single ticket, the airline is responsible for rebooking you if you miss it. For peace of mind, a layover of 75 to 90 minutes is much safer. If you do have a 55-minute window, make sure to use the "Short Connection" lanes at passport control if they are open, and move briskly as soon as the cabin doors open.