Keep in mind that in most cases it's single engine performance that is thr limiting factor. Can the airplane still climb away and meet the gradient necessary to avoid all obstacles in the engine failure takeoff path.

Poster above is correct about how bags are accounted for. Not having to gate check carryons results in a lower takeoff weight. Which, if you stop and think about it, is preposterous since the airplane is the same actual weight in both situations. The terrain you hit or don't hit when an engine fails, doesn't care how it looked on paper.,...