The HTC U11 Plus leaks are piling on - after benchmarks revealed its innards, time to gaze at the phone's exterior. Technical details put the phone at 158.2 x 74.6 x 9.1mm in size. That would make it noticeably taller than, say, an LG V30 - another phone with a 6" 18:9 screen. Thicker too, though @LlabTooFeR (who knows a thing or two about HTC phones) suggests that the U11 Plus will have a batter capacity around 4,000mAh. If that is the case, we'd be quite happy with a 9.1mm phone. Plus, the regular U11 is 153.9mm tall already so this isn't that much of an increase for the extra screen....
Source: https://www.gsmarena.com/htc_u11_plus_renders-news-27811.php