chrome.blogspot.com/2013/02/the-chromebook-pixel-for-whats-next.html

By comparison, Surface Pro is 207.82 ppi and a MacBook Pro 13" is 227 ppi. My iPhone 4s, by comparison stands tall at 326 ppi, although the next generation of phones (like HTC One) should pass it by.

Should I switch to the metric system when discussing this?