What is Page Rank?

Pagerank is the parameter which describes how important and reputed a page is on web. In short you can say PageRank is a “vote”, by all the other pages on the Web, about how significant a page is. Main support of pagerank is link provided to page. Google is also having same way of deciding page’s importance. It’s a method used by Google to determine a page’s relevance or importance. We will occasionally refer to PageRank as "PR". Higher the pagerank means higher the important of page e.g PR 6 site is more important then PR 2 site.

PageRank is also displayed on the toolbar of your browser if you’ve installed the Google toolbar ( from http://toolbar.google.com/). PR (green color line) is as show below in google toolbar.

Page rank is as show below on Google toolbar. But the Toolbar PageRank only goes from 0 – 10 and seems to be something like a logarithmic scale:

Toolbar PageRank (log base 10)	Real PageRank
0	0 - 10
1	100 - 1,000
2	1,000 - 10,000
3	10,000 - 100,000
4	and so on...

How PR calculated?

Only Inbound links are the factor to calculate PR of any page. Where inbound link means links within that site and coming from outside the side; linking to that page. Here below is equation to calculate the PR of page “A”

PR(A) = (1-d) + d(PR(t1)/C(t1) + ... + PR(tn)/C(tn))

In the equation 't1 - tn' are pages linking to page A, 'C' is the number of outbound links that a page has and 'd' is a damping factor, usually set to 0.85.