If you do the conversion from metric to English measurements, Itachi is 5'10" and 128 lbs.
I am 5'10" and 131 lbs.
I AM A TWIG AND I STILL SLIGHTLY OUTWEIGH ITACHI WHAT IS THIS.
^ Also, this is why I find all fanart of male Naruto characters that depicts them as having six-pack abs or whatever completely ridiculous. If they had that kind of muscle, they would weigh a lot more. >.>
Aaand, I feel really tall.