How much layover time do I need?
 

So I'm flying from Chicago to Germany and the flight I found has a layover in Madrid.
The layover is 2 hours and 40 minutes and I have NO idea how to check if it's in the same terminal.
Here's the link to the list of flight:
http://www.kayak.com/flights/CHI-DUS...-09/2014-08-25
And the one I'm looking at departs Chicago at 3:15 and arrives in Dusseldorf at 11:30.

Is that enough time? I shouldn't have to get my luggage right?
I'm a VERY inexperienced traveler.

Looks like IB6274 arrives at Terminal 4 and IB3622 leaves from Terminal 4.

2 hours, 40 min is fine.

Should be fine is what I meant to say. Clearing immigration quickly will be the biggest hurdle.

You'll arrive at the Terminal 4 satellite (T4S) at Barajas. You'll clear immigration/passport control, then take an automated train from T4S to the main Terminal 4, where your flight to Germany will depart. You'll go through bag claim and customs in Germany, not Madrid.

2h40m is ample time for this. If you want to speed things up, use the elevators/lifts to get from passport control to the train at T4S; the escalators take forever. T4 is huge, so give yourself plenty of time to find your departure gate.

That route is served by several airlines - to me nothing beats a non-stop flight even if the price is slightly higher.

If it were me I'd hunt around for a better price on different days for a non-stop flight.

But to answer your question, 2:40 is fine. You will NOT need to get your luggage or clear customs. Your bags will be checked through to DUS. You'll only need to pass through immigration.