PageRank is Google’s method of ranking individual web pages. Google looks at the pages that link to your page and how they rank in terms of importance. Specifically, pages that have links from important, high quality pages, receive a higher PageRank.
Google combines PageRank with sophisticated text-matching techniques to find pages, which are both important and relevant to your search. So how Google PageRank is calculated ?
The easiest way to explain the page ranking calculation at Google is to think of it as a voting system. If we place a link to someone’s web site on one of our web pages, then it means we are voting for that site.
Here’s an infograph by ZippyCart based on the voting sytem. It explains how Google Page Rank is calculated and what really matters when trying to increase your Page Rank. :