Now instead of searching for tools to figure out how many web pages a website has you can use following Google query for the purpose. Here's how

  1. Go to Google
  2. Put down query in above form
    i.e. as inurl:*
    here you replace with name of your website.
  3. The total count of query results returned shows how many pages that particular website has, like in above case Google returned 291,000,000 number. So there you are with total pages on a website.
The search results and numbers given back by Google in above case depends upon the pages indexed by Googlebot. Happy researching.