X1 Carbon - 12.72 x 8.54 x 0.59 in X280 - 12.11 x 8.26 x 0.7 in X13 - 12.2 x 8.6 x 0.7 in The X13 is the old X 12in size. I would still take the Carbon prob

X1 Carbon - 12.72 x 8.54 x 0.59 in X280 - 12.11 x 8.26 x 0.7 in X13 - 12.2 x 8.6 x 0.7 in The X13 is the old X 12in size. I would still take the Carbon probably. One thing I like about it that is underrated in reviews is its flexibility. People think they want a rigid, aluminum milled laptop, but I actually quite appreciate how the entire computer can bend slightly, as an alternative way to make it more durable.