720p -> 720 vertical pixels 1080i/1080p -> 1080 vertical pixels 4k -> 2160p -> 2160 vertical pixels

The 4k confusion comes from the decision to simply double 1080p for consumer equipment instead of going the route cinema is going with true 4k horizontal resolution and still co-opt the easy 4k name.

And really, who wants to walk around saying 2160p? Makes me want to follow up with "1.21 gigawatts!"

I do agree with a statement in an article posted here about 4k a few days back. At this point the cinema guys should toss in the towel and just use the term 4K PRO and let consumer equipment use 4k.

I don't know, 3840 is fairly close.

Yeah, but they're not vertical pixels like the other numbers are.