Google PageRank Calculation Example 1 -
All Webpages Link with Homepage (Part 1)
This is a very common internal linking structure of a web site - all web pages only link back to home page. Before proceeding to PageRank calculation, let's recall some important facts of PageRank:
- The average PageRank number of pages is always one.
- How to do PageRank Calculation step by step.
- Inbound Links will increase PageRank value of a page.
- Outbound Links will loss a portion of PageRank to the linked page.
Let's Get Started with PageRank Calculation......
Prepare Web Pages
Imagine that you just prepared some web pages for your web site. This is a small web site with only four pages - a Home Page and other three pages. This is shown as the following diagram:
As we learned that the average PageRank of all pages in a wesite is one. Therefore all pages have a PageRank value of one. Now, let's write down the PageRank number of all web pages in a tabular form. The result is shown in the following table.
| 1 | |||||||
| Home | 1.00 | ||||||
| Page 1 | 1.00 | ||||||
| Page 2 | 1.00 | ||||||
| Page 3 | 1.00 | ||||||
Total PR: |
4.00 | ||||||
PR Loss: |
0 |
Linking the Web Pages
The internal linking of web pages are shown in the following diagram:
Once you placed links to your webpages, the PageRank values of all linked pages will be changed. The final PageRank numbers of all linked pages can be calculated using the PageRank Formula.
Okay! Start PageRank Calculation......Home Page PageRank Calculation:
Let's start with the home page. Since this is the first PageRank calculation, the PageRank values of all pages will be one.
Write down the new PageRank number of Home Page in the table as shown below:
| 1 | 2 | ||||||
| Home | 1.00 | 2.70 | |||||
| Page 1 | 1.00 | ||||||
| Page 2 | 1.00 | ||||||
| Page 3 | 1.00 | ||||||
Total PR: |
4.00 | ||||||
PR Loss: |
0 |
Page 1 PageRank Calculation:
Now, calculate the PageRank value of Page 1.
Tips:
Page 1 has one Backlink from Homepage. And Homepage has 3 outbound links.
Again, write down the new PageRank number of Page 1 in the table as shown below:
| 1 | 2 | ||||||
| Home | 1.00 | 2.70 | |||||
| Page 1 | 1.00 | 0.43 | |||||
| Page 2 | 1.00 | ||||||
| Page 3 | 1.00 | ||||||
Total PR: |
4.00 | ||||||
PR Loss: |
0 |
I think you should be able to follow the PageRank calculation easily. Not so difficult is it?
Page 2 PageRank Calculation:
Now, calculate the PageRank value of Page 2. Obviously, this should be same as Page 1.
The results of the new PageRank numbers now become:
| 1 | 2 | ||||||
| Home | 1.00 | 2.70 | |||||
| Page 1 | 1.00 | 0.43 | |||||
| Page 2 | 1.00 | 0.43 | |||||
| Page 3 | 1.00 | ||||||
Total PR: |
4.00 | ||||||
PR Loss: |
0 |
Page 3 PageRank Calculation:
Now, calculate the PageRank value of Page 3. Obviously, this should be same as Page 1 and Page 2.
After the first round of calculation, the results of the new PageRank numbers now become:
| 1 | 2 | ||||||
| Home | 1.00 | 2.70 | |||||
| Page 1 | 1.00 | 0.43 | |||||
| Page 2 | 1.00 | 0.43 | |||||
| Page 3 | 1.00 | 0.43 | |||||
Total PR: |
4.00 | 4.00 | |||||
PR Loss: |
0 | 0 |
Question:
When Page 1 place a link to Home Page, the PageRank value of a Home Page has been changed. And the PageRank value of Page 1 will also be changed. If the PageRank value of Page 1 has been changed, then the PageRank value of Home Page has to be re-calculated again..........! It seems to form an endless pagerank calculation circle!
Answer:
At first glance, it seems an endless pagerank calculation circle. However the strange thing is: every time we run a PageRank calculation of a page, the PageRank value of the Page will be closer to the final value. In other words, if we repeat doing the pagerank calculation for a lot of times, the PageRank values of the pages will not be changed much or will even be stable.
Please read on and everything will be cleared up.
Tips:
Poor linking will cause PageRank Loss. Please check another example of PageRank Loss.
