OK, I bought this based on the internal size. The advertised size is right on the money, and you don't have to worry about the ''fits up to 17-inch laptops. '' I easily fit my 18. 4'' HP HDX18 in this thing. That's the good news. The bad news is this HP's big brick adapter is much larger than the older HP model I owned. The case still shuts all right, but the front combo lock has issues sealing. That's not a huge deal for security reasons since you can still use the two padlock slots on the front of the case, but it probably wouldn't be too good if I dropped it in a lake. Anyway, my next stop with this laptop and case is Afghanistan, so I'll get to (hopefully) keep my laptop safe from the elements over there. I had a Pelican for my old HP when I was in Iraq and it did a beautiful job, so I doubt I'll have any issues, and neither will you.