The only way to get a reverse phone lookup was through a private investigator, five years ago. They charged $200 and up and took like two weeks to get back to you.

The good news – Private detectives no longer exist. There are hundreds of electronic databases that contain cell phone number information and therefore can be accessed online.

The bad news – There is no nationwide cell phone directory, therefore there is no single database containing all mobile numbers in the US Some databases have more numbers and some have fewer. All of them differ from each other in:

  1. The number of phone numbers in its database: the largest has 253 million numbers, while others have only around 100 million.
  2. How often they update the information in their database: People change their cell phone plan and wireless carriers all the time. A number that belonged to person X in November 2008 may belong to person Y in April 2009. So if the database you’re using isn’t up to date, you’re screwed!
  3. The accuracy of the information in the database: Again, if the database you’re using isn’t accurate, you’re screwed!

Why can’t they share the same information?
Why are these different databases from different companies different?

Since mobile numbers are treated as confidential information, they are not published in freely accessible public telephone directories. This is why there is no National Directory of Cell Phones in the United States. This is why different databases are blocked with different sets of phone numbers based on local region and wireless carrier.

So what is the solution?

You can search any random database and you might be lucky enough to get your number from the first database you search. However, that is not 100% guaranteed. But if you use the two largest databases currently available (as of March 2009), you are 95% sure that you will get accurate information about your reverse lookup.